a cup of coffe has a temperature of 85°C when its poured and allowed to cool in a room with a temperature of 30°C. After 1 minute, the temperature of the coffee is 80°C. detrimine the temperature of the coffee at time t. how long must you wait untill the coffee is 35°C?(a) T(t)=___(b) you will have to wait approximately __ minutes untill the coffee is 25°C
(a) T(t) is calculated to be equal to 1.605 minutes (b) We are required to wait approximately 1.605 minutes (or about 1 minute and 36 seconds) until the coffee is 35°C.
We can model the temperature of the coffee as it cools down using Newton's Law of Cooling, which states that the rate of cooling of an object is proportional to the temperature difference between the object and its surroundings. In this case, we have:
T(t) = Troom + (Tinitial - Troom) x e[tex].^{-kt}[/tex]
where:
T(t) is the temperature of the coffee at time t
Troom is the temperature of the room (30°C)
Tinitial is the initial temperature of the coffee (85°C)
k is a constant that depends on the properties of the coffee and the cup
e is the mathematical constant e (approximately 2.71828)
To find k, we can use the fact that the temperature of the coffee is 80°C after 1 minute:
80 = 30 + (85 - 30) x e[tex].^{-k X 1}[/tex]
Solving for k, we get:
k = ln(11/3) ≈ -1.497
(a) To find the temperature of the coffee at time t, we can plug in the values we know into the equation:
T(t) = 30 + (85 - 30) x e[tex].^{(-1.497t)}[/tex]
(b) To find how long we need to wait until the coffee is 35°C, we can set T(t) equal to 35 and solve for t:
35 = 30 + (85 - 30) x e[tex].^{(-1.497t)}[/tex]
5/55 ≈ 0.09091 = e[tex].^{(-1.497t)}[/tex]
ln(0.09091) ≈ -2.403 = -1.497t
t ≈ 1.605 minutes
Therefore, we need to wait approximately 1.605 minutes (or about 1 minute and 36 seconds) until the coffee is 35°C.
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There are white, blue, and red boats in the marina. Two-fifths of the boats in the marina are white, 3/5 of the remaining boats are blue, and the rest are red. If there are [5x5]+45 / 5 - 22 red boats, how many boats are in the marina?
After intensively solving the question, it is clear that there are 50 boats in the marina.
How to calculate the number of boatsLet X = total number of boats in the marina
From the question, we know that: 2/5 of the boats in the marina are white, which means there are White boats = 2/5 * X
Remaining boats (total - white boats) = (1 - 2/5) * X = 3/5 * X 3/5 of the remaining boats are blue, which means: Blue boats = 3/5 * (3/5 * X) Red boats = 12
Now, we can set up an equation to solve for "x":2/5X + 3/5 * (3/5 * X) + 12 = XSimplifying the equation:2/5X + 9/25X + 12 = X
Multiplying both sides by 25:10x + 9x + 300 = 25x300 = 6xx = 50
Therefore, there are 50 boats in the marina.
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A researcher claims that the average wind speed in the desert is less than 24.3 kilometers per hour. A sample of 32 days has an average wind speed of 23 kilometers per hour. The standard deviation of the population is 2.24 kilometers per hour. At a = 0.05, is there enough evidence to reject the claim?
the calculated t-value of -2.23 is less than the critical value of -1.699, we can reject the null hypothesis and conclude that there is enough evidence to support the claim that the average wind speed in the desert is less than 24.3 kilometers per hour.
To test whether there is enough evidence to reject the claim that the average wind speed in the desert is less than 24.3 kilometers per hour, we can use a one-sample t-test. The null hypothesis is that the population mean wind speed is 24.3 kilometers per hour or greater, while the alternative hypothesis is that the population mean wind speed is less than 24.3 kilometers per hour.
Using the given information, we can calculate the test statistic as follows:
[tex]t = \frac{(23 - 24.3)} { (2.24 / \sqrt{(32}} = -2.23[/tex]
where 23 is the sample mean wind speed, 24.3 is the claimed population mean wind speed, 2.24 is the population standard deviation, and √(32) is the square root of the sample size.
Using a t-distribution table with 31 degrees of freedom (32-1), we can find the critical value for a one-tailed test with alpha = 0.05 to be -1.699. Since the calculated t-value of -2.23 is less than the critical value of -1.699, we can reject the null hypothesis and conclude that there is enough evidence to support the claim that the average wind speed in the desert is less than 24.3 kilometers per hour.
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A population standard deviation is estimated to be 11. We want to estimate the population mean within 1, with a 90-percent level of confidence. What sample size is required?For full marks round your answer up to the next whole number.Sample size: 0Question 7 [3 points]Wynn is the new statistician at a cola company. He wants to estimate the proportion of the population who enjoy their latest idea for a flavour enough to make it a successful product. Wynn wants to obtain a 99-percent confidence level estimate of the population proportion and he wants the estimate to be within 0.08 of the true proportion.a) Using only the information given above, what is the smallest sample size required?Sample size: 0
A sample size of at least 669 is required to estimate the population proportion within 0.08 with a 99% level of confidence.
To determine the sample size required to estimate the population mean within 1 with a 90% level of confidence, we can use the formula:
[tex]n = (z\alpha/2 \times \sigma / E)^2[/tex]
n is the sample size, [tex]z\alpha/2[/tex] is the z-score with a probability of [tex](1-\alpha)/2[/tex]in the upper tail, [tex]\sigma[/tex] is the population standard deviation, and E is the maximum error or margin of error.
The population standard deviation is known, we can use a z-test and look up the z-score with a probability of 0.05 (1-0.90)/2 in the upper tail in a z-table or calculator.
The value is approximately 1.645.
Plugging in the values from the problem, we get:
[tex]n = (1.645 \times 11 / 1)^2[/tex]
n = 207.57
Rounding up to the next whole number, we get:
n = 208
A sample size of at least 208 is required to estimate the population mean within 1 with a 90% level of confidence.
To determine the sample size required to estimate the population proportion within 0.08 with a 99% level of confidence, we can use the formula:
[tex]n = (z\alpha/2)^2 \times (\^p \times (1-\^p)) / E^2[/tex]
n is the sample size, [tex]z\alpha/2[/tex] is the z-score with a probability of [tex](1-\alpha)/2[/tex]in the upper tail, [tex]\^p[/tex] is the sample proportion (unknown), and E is the maximum error or margin of error.
The sample proportion is unknown, we can use a conservative estimate of 0.5 for [tex]\^p[/tex]to get a maximum sample size.
Using a z-score with a probability of [tex]0.005 (1-0.99)/2[/tex] in the upper tail, we get a value of approximately 2.576.
Plugging in the values from the problem, we get:
[tex]n = (2.576)^2 \times (0.5 \times (1-0.5)) / 0.08^2[/tex]
n = 668.86
Rounding up to the next whole number, we get:
n = 669
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A painting company will paint this wall of a building. The owner gives them the following dimensions: Window A is 6 1/4 ft times 5 3/4 ft. Window B is 3 1/8 times 4 ft. Window C is 9 1/2 ft. Door D is 4 ft times 8 ft. What is the area of the painted part of the wall?
The area of the painted part of the wall is approximately 107.56 square feet.
What is arithmetic sequence?
An arithmetic sequence is a sequence of numbers in which each term after the first is found by adding a fixed constant number, called the common difference, to the preceding term.
To calculate the area of the painted part of the wall, we need to first calculate the total area of the wall and then subtract the area of the windows and door.
Let's start by finding the area of each window and the door:
The area of Window A = 6 1/4 ft x 5 3/4 ft = (6 + 1/4) ft x (5 + 3/4) ft = 38 7/16 sq ft
The area of Window B = 3 1/8 ft x 4 ft = (3 + 1/8) ft x 4 ft = 12 1/2 sq ft
The area of Window C = 9 1/2 ft x 1 ft (we don't have the width of the window, so we assume it's 1 ft) = 9 1/2 sq ft
The area of Door D = 4 ft x 8 ft = 32 sq ft
Now, let's add up the areas of the windows and door:
Total area of windows = Area of Window A + Area of Window B + Area of Window C = 38 7/16 sq ft + 12 1/2 sq ft + 9 1/2 sq ft = 60 7/16 sq ft
Total area of door = Area of Door D = 32 sq ft
Therefore, the total area of the painted part of the wall = Total area of the wall - Total area of windows - Total area of door.
Since we don't have the dimensions of the wall, we can't calculate its total area. However, we can assume that the wall is a rectangle and that the windows and door are located in the middle of the wall. In this case, the painted area of the wall is the area of the rectangle minus the area of the windows and door.
Let's assume that the width of the wall is 20 ft and the height is 10 ft (this is just an example, you can use different values if you have different assumptions about the wall).
Area of the wall = width x height = 20 ft x 10 ft = 200 sq ft
Painted area of the wall = Area of the wall - Total area of windows - Total area of door = 200 sq ft - 60 7/16 sq ft - 32 sq ft = 107 9/16 sq ft
Therefore, the area of the painted part of the wall is approximately 107.56 square feet.
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for the following scenario, would you utilize a wilcoxon sign rank or friedman's rank test? a researcher wanted to test the ratings of three different brands of paper towels. each brand had 7 reviewers. group of answer choices wilcoxon sign rank test friedman rank test
For the following scenario where a researcher wanted to test the ratings of three different brands of paper towels with 7 reviewers each, you would utilize Friedman's rank test.
For the given scenario, the appropriate test to use would be the Friedman's rank test. This is because we have three different brands of paper towels, and each brand is rated by 7 reviewers.
The Friedman's test is used to determine if there are significant differences among the groups in a repeated measures design, where the same individuals are rated on multiple occasions. Therefore, it is the appropriate test for this scenario where the ratings are collected from multiple reviewers for each brand.
This test is also appropriate because there are more than two related groups being compared (three brands of paper towels), and the data is likely ordinal (ratings). The Wilcoxon sign rank test is typically used when comparing only two related groups.
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Convert the complex number 5cis(330°) from polar to rectangular form.
Enter your answer in a + bi form and
round all values to 3 decimal places as needed
The rectangular form of the complex number 5cis(330°) is approximately -2.500 - 4.330i.
We can convert the complex number 5cis(330°) from polar to rectangular form using the following formulas
a = r cos θ
b = r sin θ
where r is the magnitude of the complex number and θ is the argument of the complex number.
In this case, the magnitude is 5 and the argument is 330°. We need to convert the argument to radians by multiplying it by π/180
330° × π/180 = 11π/6 radians
Now we can use the formulas to find a and b
a = 5 cos (11π/6) ≈ -2.500
b = 5 sin (11π/6) ≈ -4.330i
Therefore, the rectangular form of the complex number is approximately
-2.500 - 4.330i
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6) an acceptable residual plot exhibits a) increasing error variance. b) decreasing error variance. c) constant error variance. d) a curved pattern. e) a mixture of increasing and decreasing error variance.
An acceptable residual plot exhibits constant error variance. Therefore, option c) is correct.
An acceptable residual plot exhibits c) constant error variance. This means that the spread of the residuals is consistent across all values of the predictor variable, indicating that the model's assumptions are being met.
Residual plots with increasing or decreasing error variance (a or b) suggest that the model is not adequately capturing the relationship between the predictor and response variables.
A curved pattern (d) suggests that the model is not linear and may require a different approach, such as a quadratic or logarithmic model.
A mixture of increasing and decreasing error variance (e) suggests that the model may not be appropriate for the data and may need to be revised.
In a good residual plot, the points should be randomly scattered around the horizontal axis, showing no discernible pattern, and maintaining a constant variance throughout. This indicates that the model's assumptions are met and its predictions are reliable.
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During one recent year, U.S. consumers redeemed 6.79 billion manufacturers' coupons and saved themselves $2.52 billion. Calculate and interpret the mean savings per coupon.
The mean savings per coupon during this recent year was approximately $0.37
To calculate the mean savings per coupon during the recent year when U.S. consumers redeemed 6.79 billion manufacturers' coupons and saved themselves $2.52 billion, follow these steps:
1. Identify the total number of coupons redeemed: 6.79 billion.
2. Identify the total amount saved: $2.52 billion.
3. Divide the total amount saved by the total number of coupons redeemed to find the mean savings per coupon.
Mean savings per coupon = Total amount saved / Total number of coupons redeemed
Mean savings per coupon = $2.52 billion / 6.79 billion
Mean savings per coupon ≈ $0.37
So, on average, U.S. consumers saved $0.37 per manufacturer's coupon redeemed during the given year. This means that, on average, consumers saved 37 cents for each manufacturer's coupon they redeemed.
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Question 1 (1 point) MC1 A statistics company found that 10% of people were smokers in a random sample of 500 Qatar residents. Based on this, The Peninsula News reported that about 10% of all Qatar residents are smokers." Which term best describes the report Pennsula News was making? A) Descriptive statistics 4: OB) Census C) Population ce 5: D) Inferential statistics
A population is the entire group of individuals or objects that we are interested in studying, while a sample is a subset of the population that is actually observed or surveyed.
D) Inferential statistics is the term that best describes the report by The Peninsula News.
Inferential statistics involves making predictions or generalizations about a population based on data from a sample. In this case, the statistics company surveyed a random sample of 500 Qatar residents and found that 10% of them were smokers. The Peninsula News then used this sample data to make an inference about the population of all Qatar residents, stating that about 10% of them are smokers.
This inference is made by assuming that the sample is representative of the population, and using statistical techniques to estimate the population parameters based on the sample statistics. Inferential statistics is used when it is not feasible or practical to survey the entire population, as is often the case in large or diverse populations.
In contrast, descriptive statistics is used to summarize and describe the characteristics of a sample or population, without making any inferences about the larger population. A census is a type of survey that attempts to collect data from the entire population, rather than just a sample. A population is the entire group of individuals or objects that we are interested in studying, while a sample is a subset of the population that is actually observed or surveyed.
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The range of the random variable X is {1, 2, 3, 6, u}, where u is unknown. If each value is equally likely and the mean of X is 10, determine the value of u.
The value of u is 38.
To find the value of u, we first need to calculate the sum of all the values in the range of X.
1 + 2 + 3 + 6 + u = 12 + u
Since each value is equally likely, we can calculate the expected value of X using the formula:
E(X) = (1/5) * (1 + 2 + 3 + 6 + u) = (12 + u)/5
We know that the mean of X is 10, so we can set the expected value equal to 10 and solve for u:
(12 + u)/5 = 10
12 + u = 50
u = 38
Therefore, the value of u is 38.
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Simplify: 100 ÷ 4 × 5 A. 125 B. 1,250 C. 5 D. 2,000
On simplification of 100 ÷ 4 × 5, we get 125. Thus, the correct answer is A
For simplification, we follow the rule of BODMAS. This rule states that one solves the equation in the following order: Brackets, Exponents or Order, Division, Multiplication, Addition, and Subtraction in order to get the right answer.
According to this rule, we first solve the Division operation
=100 ÷ 4 × 5
=25 x 5
Then one has to solve the multiplication operation.
=25 x 5
=125
Therefore on simplification using the BODMAS rule of 100 ÷ 4 × 5, we get 125 as the result.
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17. To estimate the number of white-tailed
deer in Minnesota, biologists captured and
tagged 650 deer and then released them
back into the woods. One year later, the
biologists captured 300 deer and counted 6
deer with tags. Estimate the actual number
of deer in the forest.
A. 30,600
B. 30,100
C. 29,050
D. 32,500 please help
The estimate can be found by setting up a proportion:tagged deer in first sample / total population = tagged deer in second sample / size of second sample.Solving for x, we get:x = (650 x 300) / 6 = 32,500.Therefore, the estimated actual number of deer in the forest is D) 32,500.
What is Proportion?Proportion is a mathematical concept that compares two ratios or fractions, stating that they are equivalent. It is often used in real-life situations to solve problems related to rates, percentages, and other related topics.
What is population?Population refers to the total number of individuals, objects, events, or other items in a particular group or category, often used in statistics or social sciences.
According to the given information:
This is an example of a capture-recapture (or mark-recapture) method to estimate the size of a population. The general idea is to capture a sample of the population, mark or tag them, release them back into the population, and then capture another sample at a later time. By comparing the number of tagged individuals in the second sample to the total sample, an estimate of the population size can be made.
In this case, the proportion of tagged deer in the second sample (6/300) should be approximately equal to the proportion of tagged deer in the total population (650/x), where x is the total number of deer in the forest. We can set up a proportion:
6/300 = 650/x
Cross-multiplying, we get:
6x = 300 × 650
Solving for x, we get:
x = 300 × 650 / 6
x = 32,500
Therefore, the estimated actual number of deer in the forest is 32,500 (option D).
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An ellipse is centered at the origin. Recall that ellipses have (potentially) different horizontal and vertical radii. Let A and B be the horizontal and vertical radii lengths, respectively. Assume that A, B ~ Exp(1) and are independent. Recall that the area of an ellipse with radii a and b is given by mab. a) Find the expected area of the ellipse. b) Given that B = b, find the conditional distribution of the area of the ellipse. c) Suppose that while the ellipse is being created, a circle with diameter A is being created at the same time. Find the probability the area of the circle is larger than the area of the ellipse.
a) The area of an ellipse with radii A and B is given by A = πAB. Using the fact that A and B are independent exponential random variables with rate parameter 1, we can find the expected value of the area as follows:
E[A] = E[πAB] = πE[A]E[B] = π(1/1)(1/1) = π
Therefore, the expected area of the ellipse is π.
b) Given that B = b, the conditional distribution of A is still exponential with rate parameter 1, since A and B are independent. Therefore, the conditional distribution of the area of the ellipse is given by:
f(A|B=b) = f(A,B=b)/f(B=b) = (1/e^A)(1/e^b)/(1/e^b) = (1/e^A)
for A > 0.
c) The area of the circle with diameter A is given by Ac = π(A/2)^2 = πA^2/4. The probability that the area of the circle is larger than the area of the ellipse is given by:
P(Ac > A) = P(πA^2/4 > πAB) = P(A/4 > B)
Since A and B are independent exponential random variables with rate parameter 1, the distribution of A/4 given B=b is exponential with rate parameter 4. Therefore, we can compute the probability as follows:
P(Ac > A) = E[P(A/4 > B)] = E[∫_0^A/4 4e^(-4b) db] = ∫_0^∞ 4e^(-4b) (1-e^(-A/4)) db
= (1-e^(-A/4))
Therefore, the probability that the area of the circle is larger than the area of the ellipse is 1-e^(-A/4).
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Let denote the sample mean of a random sample of size n1 = 16 taken from a normal distribution N(212, 36), and let denote the sample mean of a random sample of size n2 = 25 taken from a different normal distribution N(212, 9). Compute
The difference between the two sample means is 0, which suggests that there is no significant difference between the two populations.
To compute the difference between the two sample means, we can use the formula:
Z = (X1 - X2) / SE
where X1 and X2 are the sample means, and SE is the standard error of the difference between the means, given by:
SE = √((s1² / n1) + (s2² / n2))
where s1 and s2 are the sample standard deviations.
Substituting the given values, we get:
X1 = 212, s1 = 6, n1 = 16
X2 = 212, s2 = 3, n2 = 25
SE = √((6² / 16) + (3² / 25)) = 1.553
Z = (212 - 212) / 1.553 = 0
Therefore, the difference between the two sample means is 0, which suggests that there is no significant difference between the two populations.
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A motoring magazine collected data on cars on a particular stretch of road.
Certain details on 800 cars were recorded.
(i) The ages of the 800 cars were recorded. 174 of them were new (less than 1 year old).
Find the 95% confidence interval for the proportion of new cars on this road.
Give your answer correct to 4 significant figures.
The 95% confidence interval for the proportion of new cars on this road is (0.1903, 0.2337).
To calculate the 95% confidence interval for the proportion of new cars, follow these steps:
1. Determine the sample proportion (p-hat): 174 new cars out of 800 total cars gives p-hat = 174/800 = 0.2175.
2. Find the standard error (SE) for the sample proportion: SE = sqrt[(p-hat * (1 - p-hat))/n] = sqrt[(0.2175 * 0.7825)/800] ≈ 0.0111.
3. Identify the critical value (z*) for a 95% confidence interval: z* ≈ 1.96.
4. Calculate the margin of error (ME): ME = z* * SE ≈ 1.96 * 0.0111 ≈ 0.0217.
5. Determine the lower and upper bounds of the confidence interval: Lower Bound = p-hat - ME = 0.2175 - 0.0217 = 0.1903; Upper Bound = p-hat + ME = 0.2175 + 0.0217 = 0.2337.
Therefore, the 95% confidence interval for the proportion of new cars on this road is (0.1903, 0.2337), correct to 4 significant figures.
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a theater sells tickets for a movie. tickets for children are $6.25 and adult tickets are $8.25. The theater sells 200 tickets for $1500.00. how many tickets of each type were sold?
On solving the equations, the number of children ticket and adult ticket sold is 75 and 125 respectively.
What is an equation?
A mathematical definition of an equation is a claim that two expressions are equal when they are joined by the equals sign ("=").
Let's use a system of equations to solve the problem -
Let x be the number of children's tickets sold, and y be the number of adult tickets sold.
From the problem, we know -
x + y = 200 (equation 1) (the total number of tickets sold is 200)
6.25x + 8.25y = 1500 (equation 2) (the total revenue from ticket sales is $1500)
We can solve for one of the variables in equation 1 and substitute into equation 2 -
x + y = 200
y = 200 - x
6.25x + 8.25(200 - x) = 1500
Simplifying and solving for x -
6.25x + 1650 - 8.25x = 1500
-2x = -150
x = 75
So 75 children's tickets were sold.
We can substitute this value back into equation 1 to find y -
x + y = 200
75 + y = 200
y = 125
So 125 adult tickets were sold.
Therefore, the theater sold 75 children's tickets and 125 adult tickets.
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You may need to use the appropriate technology to answer this question.
The following table contains observed frequencies for a sample of 200.
Row
Variable Column Variable
A B C
P 22 46 52
Q 28 24 28
Test for independence of the row and column variables using = 0.05.
a)Find the value of the test statistic. (Round your answer to three decimal places.)
b) Find the p-value. (Round your answer to four decimal places.)
a). The value of the test statistic is 9.864.
b). Using a chi-square table, the p-value is 0.0020.
What is test statistic?The chi-square statistic, which is determined by deducting the anticipated frequency for each cell from the observed frequency and then squareing the result, is the test statistic for this issue.
a). By multiplying the row total by the column total and dividing the result by the sample size, the predicted frequency for each cell is determined.
The formula is [tex]X^2=\sum\frac{(O-E)2}{E}[/tex]
Where O denotes frequency observed, and E denotes frequency anticipated.
The anticipated frequency for cells A and B is = (22*46)/200
= 20.2.
The chi-square statistic is calculated as follows:
[tex]X^2[/tex] = (22-20.2)2/20.2 + (46-20.2)2/20.2 + (52-20.2)2/20.2
= 3.912
The anticipated frequency for cells B and C = (46*28)/200
= 12.96.
The chi-square statistic is calculated as follows:
[tex]X^2[/tex] = (24-12.96)2/12.96 + (28-12.96)2/12.96 + (28-12.96)2/12.96
= 5.952
Consequently, the test statistic's value is = 3.912 + 5.952
= 9.864.
b). The probability of getting a test statistic at least as extreme as the value determined in component (a) is known as the p-value.
In this issue, the degrees of freedom are (r-1)(c-1).
= (2-1)(3-1)
= 2
The region to the right of the test statistic under the chi-square distribution with two degrees of freedom, then, represents the p-value. The p-value using a chi-square table is 0.0020.
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PLEASE HELP WILL MARK BRAINLIEST!
Answer:
156 units²
Step-by-step explanation:
You want the area of the right trapezoid shown with bases 10 and 3, and height 24.
TrapezoidThe area of a trapezoid is given by the formula ...
A = 1/2(b1 +b2)h
where b1 and b2 are the parallel bases, and h is the distance between them.
ApplicationHere, the area is ...
A = 1/2(3 +10)(24) = 156 . . . . square units
The area of the shape is 156 units².
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A teacher wants to choose a student at random. The teacher decides to choose the first person to walk through the classroom door at the start of the lesson. Explain why this is not a good method
Selecting the first person to walk through the classroom door at the start of the lesson is not a good method as it is not a representative sample of the entire class.
What is a Biased sample?A biased sample is a sample that is not representative of the population from which it is drawn. This can occur when the method of sampling is flawed, or when certain members of the population are more likely to be included in the sample than others.
Here we have
A teacher wants to choose a student at random. The teacher decides to choose the first person to walk through the classroom door at the start of the lesson.
Choosing the first person to walk through the classroom door at the start of the lesson is not a good method for selecting a student at random because it can introduce bias into the selection process.
For example, if the classroom door is located near the front of the school, the students who arrive early and are closer to the door have a higher chance of being selected than those who arrive later and are farther away. This may not be a representative sample of the entire class.
Additionally, the method relies on chance and may not be fair. For example, if the first person to walk through the door happens to be a friend of the teacher, the selection may not be random and may appear to be biased.
Therefore,
Selecting the first person to walk through the classroom door at the start of the lesson is not a good method as it is not a representative sample of the entire class.
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Assume that the heights of men are normally distributed with a mean of 69.8 inches and a standard deviation of 2.4 inches. If 36 men are randomly selected, find the probability that they have a mean height greater than 70.8 inches.
The probability that 36 randomly selected men have a mean height greater than 70.8 inches is 0.0062 or 0.62%.
To solve this problem, we can use the central limit theorem and the formula for the z-score.
First, we need to calculate the standard error of the mean, which is the standard deviation divided by the square root of the sample size:
standard error of the mean = 2.4 / √(36) = 0.4
Next, we can calculate the z-score for a sample mean of 70.8 inches:
z = (70.8 - 69.8) / 0.4 = 2.5
We can use a standard normal distribution table or calculator to find the probability that the z-score is greater than 2.5. This probability is approximately 0.0062 or 0.62%.
Therefore, the probability that 36 randomly selected men have a mean height greater than 70.8 inches is 0.0062 or 0.62%.
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Assume that there is an average of 12 earthquakes in the world per month Find the probability that in a given month, there will be 13 earthquakes. Round your answer to 4 places after the decimal point, if necessary, P(x + 13) Submit Question
The probability of there being exactly 13 earthquakes in a given month, assuming an average of 12 earthquakes, is 0.1008.
We can use the Poisson distribution, which is a probability distribution that can be used to calculate the probability of a certain number of events occurring in a given time period.
In this case, we can assume that the number of earthquakes in a month follows a Poisson distribution with a mean of 12. This means that the average number of earthquakes in a month is 12, but the actual number can vary.
To find the probability that there will be 13 earthquakes in a given month, we can use the Poisson probability formula:
P(x = k) = (e(-λ) * λk) / k!
Where:
- k is the number of events we're interested in (in this case, 13)
- λ is the mean or average number of events (in this case, 12)
- e is the mathematical constant e (approximately equal to 2.71828)
- k! is the factorial of k (i.e., k x (k-1) x (k-2) x ... x 2 x 1)
Plugging in the values for k and λ, we get:
P(x = 13) = (e-12) * 1213) / 13!
Simplifying this expression, we get:
P(x = 13) = 0.1008 (rounded to four decimal places)
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Determine the null and alternative hypotheses. The principal of a middle school claims that the seventh grade test scores at her school vary less than the test scores of seventh-graders at neighboring schools, which have variation described by σ=14.7
.
A.H0:σ=14.7;Ha:σ<14.7
B.H0:σ=14.7;Ha:σ>14.7
C.H0:σ=14.7;Ha:σ≤14.7
D.H0:σ=14.7;Ha:σ≠14.7
E.H0:σ=14.7;Ha:σ≥14.7
The null and alternative hypotheses for the given scenario are:
H0: σ = 14.7
Ha: σ < 14.7
The given scenario involves testing a claim made by the principal of a middle school that the test scores of seventh-graders in her school vary less than the test scores of seventh-graders in neighboring schools, which have a variation of σ = 14.7. The null hypothesis (H0) in this case is that the standard deviation of test scores in the principal's school is equal to the standard deviation of test scores in neighboring schools, which is 14.7. The alternative hypothesis (Ha) is that the standard deviation of test scores in the principal's school is less than 14.7.
To test these hypotheses, one could conduct a one-tailed z-test for the population standard deviation. The test statistic would be calculated as:
z = (s - σ) / (σ / √(n))
Where s is the sample standard deviation, σ is the hypothesized population standard deviation, and n is the sample size. The p-value for this test would be calculated based on the z-score and the directionality of the alternative hypothesis. If the p-value is less than the significance level (α), the null hypothesis would be rejected in favor of the alternative hypothesis.
Therefore, in conclusion, the correct answer is option A, and the null and alternative hypotheses for this scenario are H0: σ = 14.7 and Ha: σ < 14.7.
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When identifying with the parts of the packaged data model that apply to your organization, you should first start with:
When identifying the parts of a packaged data model that apply to your organization, you should first start with understanding your Organization's specific needs and requirements.
This involves the following steps:
1. Assess your organization's business processes and goals, which helps in identifying key areas where data modeling can enhance decision-making and performance.
2. Analyze existing data sources and systems to understand the current data landscape, including its structure, relationships, and data quality.
3. Identify the critical data elements that align with your organization's needs, such as customer information, sales data, or financial data. These elements form the foundation of your data model.
4. Determine the relevant industry-standard data models or frameworks that can serve as a starting point for your organization's data model. This may include industry-specific models or general models applicable to a variety of businesses.
5. Evaluate the suitability of the selected packaged data model for your organization by comparing its features, flexibility, and scalability with your specific requirements.
6. Customize the chosen data model to fit your organization's unique processes, data structures, and business rules, ensuring that it accurately represents your data environment.
7. Implement and maintain the data model, regularly updating it to reflect changes in your organization's processes, data sources, or business objectives.
By following these steps, you will effectively identify and apply the parts of a packaged data model that best suit your organization's needs, enabling improved decision-making and performance.
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8. [0/1 Points] DETAILS PREVIOUS ANSWERS Solve the differential equation. 4 dy/dθ = e^y sin^2(θ)/ y sec(θ) Need Help? Read It Submit Answer 9. [0/1 Points] DETAILS PREVIOUS ANSWERS Solve the differential
To solve the given differential equation, 4 dy/dθ = [tex]e^{y}[/tex] sin²(θ) / y sec(θ), follow these steps:
Step 1: Simplify the equation
The given equation is 4 dy/dθ = [tex]e^{y}[/tex] sin²(θ) / y sec(θ). We can simplify this by recalling that sec(θ) = 1/cos(θ), so we get:
4 dy/dθ = [tex]e^{y}[/tex] sin²(θ) / (y cos(θ))
Step 2: Separate the variables
Now we want to separate the variables y and θ. We can do this by multiplying both sides by y cos(θ) and dividing both sides by [tex]e^{y}[/tex] sin²(θ):
4 y cos(θ) dy = ( [tex]e^{y}[/tex] sin²(θ)) dθ
Step 3: Integrate both sides
Now we integrate both sides of the equation with respect to their respective variables:
∫ 4 y cos(θ) dy = ∫ [tex]e^{y}[/tex] sin²(θ) dθ
Step 4: Solve the integrals
Unfortunately, both integrals are non-elementary and cannot be expressed in terms of elementary functions. However, if you are given boundary conditions or a specific range, you can evaluate these integrals numerically using various techniques, such as Simpson's rule or numerical integration software.
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Let X1, X2, ..., X_N be independent binomial(n,p) random vari- ables. What is the distribution of the sample average X= 1/N sigma^N_i=1 Xi?
The distribution of the sample average X = (1/N) * sigma^N_i=1 Xi is a normal distribution with mean E(X) = np and variance Var(X) = (p(1-p))/N.
The distribution of the sample average X can be found using the following steps:
1. Recognize that the random variables X1, X2, ..., X_N are independent and follow a binomial distribution with parameters n and p.
2. Calculate the expected value (E) and variance (Var) of a single binomial random variable Xi. For a binomial distribution, E(Xi) = np and Var(Xi) = np(1-p).
3. Define the sum of the random variables as Y = Σ^(N_i=1) Xi. Since the random variables are independent, E(Y) = N * E(Xi) = N * np and Var(Y) = N * Var(Xi) = N * np(1-p).
4. Calculate the sample average X = Y/N, which is a transformation of the sum Y. Apply the transformation rule for expected value and variance: E(X) = E(Y/N) = (N * np) / N = np, and Var(X) = Var(Y/N) = (N * np(1-p)) / N^2 = (np(1-p)) / N.
5. As N becomes large, the distribution of the sample average X approaches a normal distribution according to the Central Limit Theorem. The normal distribution has mean μ = np and variance σ^2 = (np(1-p)) / N.
Therefore, the distribution of the sample average X is approximately normal with mean μ = np and variance σ^2 = (np(1-p)) / N.
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He solution to a system of equations is _____________. A) the sum of the slopes of two lines b) the point where two lines intersect c) the combination of the y-intercepts d) the ordered pair that makes both equations true Question 13 options: 1) only d 2) both a and b 3) both b and d 4) only b
The solution to a system of equations is the point where two lines intersect, the correct option is (b).
The "Solution" to a system of equations is defined as set-of-values for the variables which make all the equations in the system true.
It is the point where all the equations in the system intersect or satisfy each other.
So, the "Solution" to a system of equations is the point where two-lines intersect, which is represented by an ordered-pair (x, y) that satisfies both equations simultaneously.
Therefore, Option (b) is correct.
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The given question is incomplete, the complete question is
The solution to a system of equations is _____________.
(a) the sum of the slopes of two lines
(b) the point where two lines intersect
(c) the combination of the y-intercepts
(d) the ordered pair that makes both equations true
The correct option is
(1) only (d)
(2) both (a) and (b)
(3) both (b) and (d)
(4) only (b).
Find the interval [ μ−z σn√,μ+z σn√μ−z σn,μ+z σn ] within which 95 percent of the sample means would be expected to fall, assuming that each sample is from a normal population.
(a) μ = 161, σ = 12, n = 47. (Round your answers to 2 decimal places.)
The 95% range is from to .
(b) μ = 1,317, σ = 21, n = 10. (Round your answers to 2 decimal places.)
The 95% range is from to .
(c) μ = 70, σ = 1, n = 27. (Round your answers to 3 decimal places.)
The 95% range is from 154.47 to 167.53.
The 95% range is from 1295.51 to 1338.49.
The 95% range is from 69.599 to 70.401.
(a) Using the formula, we get:
[161 - z(12/√47), 161 + z(12/√47)]
To find the value of z, we need to look at the standard normal distribution table for the 0.025 and 0.975 percentiles (since we want the middle 95%). The z-scores corresponding to these percentiles are -1.96 and 1.96, respectively.
So, the interval is:
[161 - 1.96(12/√47), 161 + 1.96(12/√47)]
= [154.47, 167.53]
(b) Using the same formula, we get:
[1317 - z(21/√10), 1317 + z(21/√10)]
Looking up the z-scores for the 0.025 and 0.975 percentiles, we get -2.26 and 2.26, respectively.
So, the interval is:
[1317 - 2.26(21/√10), 1317 + 2.26(21/√10)]
= [1295.51, 1338.49]
(c) Using the same formula again, we get:
[70 - z(1/√27), 70 + z(1/√27)]
This time, looking up the z-scores for the 0.025 and 0.975 percentiles, we get -1.96 and 1.96, respectively.
So, the interval is:
[70 - 1.96(1/√27), 70 + 1.96(1/√27)]
= [69.599, 70.401]
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The following data give the distribution of the types of houses in a town containing 22,000 houses:House TypecapegarrisonsplitFrequency550088007700Percentage25%35%40%
The distribution of the types of houses in the town is as follows:
- 25% of houses are Cape houses
- 35% of houses are Garrison houses
- 40% of houses are Split houses.
According to the given data, there are 22,000 houses in the town and they are classified into three types: Cape, Garrison, and Split. The frequency of Cape houses is 5,500, the frequency of Garrison houses is 8,800, and the frequency of Split houses is 7,700.
To find the percentage of each house type, we need to use the formula:
Percentage = (Frequency / Total number of houses) x 100
For Cape houses, the percentage is (5,500 / 22,000) x 100 = 25%
For Garrison houses, the percentage is (8,800 / 22,000) x 100 = 35%
For Split houses, the percentage is (7,700 / 22,000) x 100 = 40%
Therefore, the distribution of the types of houses in the town is as follows:
- 25% of houses are Cape houses
- 35% of houses are Garrison houses
- 40% of houses are Split houses.
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Ariana solved the equation as shown. Explain her error and correct the solution.
9x² - 144= 0
9x² = 144
x² = 16
√ x² = √ 16
x=+8