Alex and Bryan are giving an exam. The probability Alex gets an A is 0.9, the probability Bryan gets an A is 0.8 and the probability Alex gets an A and Bryan doesn't get an A is 0.1. What is the probability that either Alex or Bryan get an A.

Answer:

The 80% confidence interval for the population mean is between 28.32 characters and 31.68 characters.

Step-by-step explanation:

We have the standard deviation for the population, so we can use the normal distribution. If we had the standard deviation for the sample, we would have to use the t-distribution.

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1-0.8}{2} = 0.1[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].

So it is z with a pvalue of [tex]1-0.5 = 0.9[/tex], so [tex]z = 1.282[/tex]

Now, find the margin of error M as such

[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

[tex]M = 1.282*\frac{6}{\sqrt{21}} = 1.68[/tex]

The lower end of the interval is the sample mean subtracted by M. So it is 30 - 1.68 = 28.32 characters.

The upper end of the interval is the sample mean added to M. So it is 30 + 1.68 = 31.68 characters.

The 80% confidence interval for the population mean is between 28.32 characters and 31.68 characters.

Answer:

6.68% probability that the mean weight is below 68.5g.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question:

[tex]\mu = 70, \sigma = 2, n = 4, s = \frac{2}{\sqrt{4}} = 1[/tex]

Probability that the mean weight is below 68.5g:

This is 1 subtracted by the pvalue of Z when X = 68.5. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{68.5 - 70}{1}[/tex]

[tex]Z = -1.5[/tex]

[tex]Z = -1.5[/tex] has a pvalue of 0.0668

6.68% probability that the mean weight is below 68.5g.

Answer:

P(x ∠ 68.5) = 0.07

Step-by-step explanation:

Got it right on khan.

Answer:

Step-by-step explanation:

Hello!

Given the variables

Y: standardized history test score in third grade.

X₁: final percentage in history class.

X₂: number of absences per student.

Determine the following multiple regression values.

I've estimated the multiple regression equation using statistics software:

^Y= a + b₁X₁ + b₂X₂

a= 118.68

b₁= 3.61

b₂= -3.61

^Y= 118.68 + 3.61X₁ - 3.61X₂

ANOVA Regression model:

Sum of Square:

SS regression: 25653.86

SS Total: 36819.23

F-ratio: 11.49

p-value: 0.0026

Se²= MMError= 1116.54

Hypothesis for the number of absences:

H₀: β₂=0

H₁: β₂≠0

Assuming α:0.05

p-value: 0.4645

The p-value is greater than the significance level, the decision is to not reject the null hypothesis. Then at 5% significance level, there is no evidence to reject the null hypothesis. You can conclude that there is no modification of the test score every time the number of absences increases one unit.

I hope this helps!

Answer:

P = 0.5207

Step-by-step explanation:

First, we have three options: Just the first card is a diamond or an ace, Just the second card is a diamond or an ace and both cards are diamonds or aces.

Additionally, there are 16 cards that are diamond or aces in a standard deck of 52 cards (13 diamonds and 3 aces that are not diamonds). It means that there are 36 cards that are not diamond or aces (52 - 16 = 36).

So, the probability that just the first card is a diamond or an ace is calculated as:

[tex]P_1=\frac{16}{52}*\frac{36}{52}=0.2130[/tex]

At the same way, the probability that just the second card is a diamond or an ace is:

[tex]P_2=\frac{36}{52}*\frac{16}{52}=0.2130[/tex]

Finally, the probability that both cards are diamonds or aces is:

[tex]P_3=\frac{16}{52}*\frac{16}{52}=0.0947[/tex]

Therefore, the probability that at least one of the cards is a diamond or an ace is:

[tex]P=P_1+P_2+P_3\\P=0.2130+0.2130+0.0947\\P=0.5207[/tex]

Answer:

A. The causal connection is valid. Students who spend more time and effort studying will be able to memorize more​ information, so their test grades will be higher.

Step-by-step Explanation:

The causal connection between the test grades of students and the amount of time and effort spent the students spend in studying and preparing for the test appears to be valid. This is valid because students who spend more time and effort studying would most likely be able to memorize more information of which they are most likely to come by in the test they take. Invariably, they'd be able to easily recall what they've memorize and give the right answers to the questions they are asked in the test, and this definitely will earn them higher test grades.

Answer:

The speed of the river is 2mph.

Step-by-step explanation:

I guess that we want to find the speed of the river.

First, remember the relation: speed*time = distance

If the speed of the river is Sr, when Luvenia moves downstream (in the same direction that the flow of the water) the total speed will be equal to the speed of Luvenia in still water plus the speed of the water:

Sd = 4mph + Sr

and at this speed, in a time T, she can move 21 miles, so we have:

Sd*T = (4mph + Sr)*T = 21 mi

When moving upstream, the speed will be:

Su = (4mph - Sr)

and in the same time T as before, she moves 7 miles, so we have the equation:

Su*T = (4mph - Sr)*T = 7 mi

Then we have two equations:

(4mph + Sr)*T = 21 mi

(4mph - Sr)*T = 7 mi

Now we can take the quotient of those two equations and get:

((4mph + Sr)*T)/((4mph - Sr)*T) = 21/7

The time T vanishes, and we can solve it for Sr.

(4mph + Sr)/(4mph - Sr) = 3

4mph + Sr = 3*(4mph - Sr) = 12mph - 3*Sr

4*Sr = 12mph - 4mph = 8mph

Sr = 8mph/4 = 2mph.

Answer:

if the 5 numbers are different, the maximum difference is 64

Step-by-step explanation:

We have 5 positive (different) integers, a, b, c, d and e (suppose that are ordered from least to largest, so a is the smallest and b is the largest.

The mean will be:

M = (a + b + c + d + e)/5 = 15.

Now, if we want to find the largest difference between a and e, then we must first select the first 4 numbers as the smallest numbers possible, this is:

a = 1, b = 2, c = 3 and d = 4

M = (1 + 2 + 3 + 4 + d)/5 = 15

M = (10 + d)/5 = 15

10 + d = 15*5 = 75

d = 75 - 10 = 65

then the difference between a and d is = 65 - 1 = 64.

Now, if we take any of the first 4 numbers a little bit bigger, then we will see that the value of d must be smaller, and the difference between d and a will be smaller.

Answer:

16

Step-by-step explanation:

There are three possible equations: the first is used for inputs (x-values) in between negative infinity and -7, the second for inputs in between -7 and 2, and the third for inputs in between 2 and infinity. 7 is in between 2 and infinity so the third equation is applicable.

[tex]g(x)=(x+1)(x-5)[/tex]

[tex]g(7)=(7+1)(7-5)[/tex] Plug in the values

[tex]g(7)=(8)(2)[/tex] Simplify

[tex]g(7)=16[/tex]

Answer: The new price of  the car is $41856

Step-by-step explanation:

So we know the the original price as 43,600 which is 100% and is being dropped by 4%  so you would have to subtract 4% from a 100% and multiply it by the original price.

100% - 4% = 96%

Now 96% of the original price is the new price.

96% * 43,600= ?

0.96 * 43,600 = 41856

Answer:

the answer is 6!!!!!!

Step-by-step explanation:

The missing value in the table is 5

The slope of the line is the ratio of the rise to the run, or rise divided by the run. It describes the steepness of line in the coordinate plane.

The slope intercept form of a line is y=mx+b, where m is slope and b is the y intercept.

The slope of line passing through two points (x₁, y₁) and (x₂, y₂) is

m=y₂-y₁/x₂-x₁

An intravenous fluid is infused at the rate shown in the table

Minutes         Milliliters

3                            4

?                             12

2.                            3

?                             6

3                             9

9                             24

Slope=24-9/9-3

=15/3

=5

Now 5=12-4/x-3

5=8/x-3

5x-15=8

5x=23

x=23/5

x=4.6

x=5

The missing number is 5.

Hence, the missing value in the table is 5

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Answer:

The value of the function f(x) at x=a can be determined by substituting a instead of x into the function expression.

1. When x=-1, then

f(-1) = 2 * (-1)^3 - 3 * (-1)^2 + 7 = -2 - 3 + 7 = 2.

2. When x=1, then

f(1) = 2 * 1^3 - 3 * 1^2 + 7 = 2 - 3 + 7 = 6.

3. When x=2, then

f(-1) = 2 * 2^3 - 3 * 2^2 + 7 = 16 - 12 + 7 = 11.

Step-by-step explanation:

Answer:

f(−1) =✔ 2

f(1) = ✔ 6

f(2) =✔ 11

Step-by-step explanation:

Answer: -6m-n+3

Step-by-step explanation:

The answer is -6m-n+3 because -3

times 2m is -6m and -n stays the same its outside of the parenthesis

and lastly -3 times -1 is positive 3

so answer maches up with the last one

the answer is -6m-n+3

Hope this helps :)

Answer:

-6m-n+3

Step-by-step explanation:

-3 x 2 is -6m (n stays same)

-3 x -1 is whole or positive 3

put it together and u get -6m-n+3

hope this helps

Answer:

The value 155 is zero standard deviations from the [population] mean, because [tex] \\ x = \mu[/tex], and therefore [tex] \\ z = 0[/tex].

Step-by-step explanation:

The key concept we need to manage here is the z-scores (or standardized values), and we can obtain a z-score using the next formula:

[tex] \\ z = \frac{x - \mu}{\sigma}[/tex] [1]

Where

Carefully looking at [1], we can interpret it as the distance from the mean of a raw value in standard deviations units. When the z-score is negative indicates that the raw score, x, is below the population mean, [tex] \\ \mu[/tex]. Conversely, a positive z-score is telling us that x is above the population mean. A z-score is also fundamental when determining probabilities using the standard normal distribution.

For example, think about a z-score = 1. In this case, the raw score is, after being standardized using [1], one standard deviation above from the population mean. A z-score = -1 is also one standard deviation from the mean but below it.

These standardized values have always the same probability in the standard normal distribution, and this is the advantage of using it for calculating probabilities for normally distributed data.

A subject earns a score of 155. How many standard deviations from the mean is the value 155?

From the question, we know that:

Having into account all the previous information, we can say that the raw score, x = 155, is zero standard deviations units from the mean. The subject   earned a score that equals the population mean. Then, using [1]:

[tex] \\ z = \frac{x - \mu}{\sigma}[/tex]

[tex] \\ z = \frac{155 - 155}{50}[/tex]

[tex] \\ z = \frac{0}{50}[/tex]

[tex] \\ z = 0[/tex]

As we say before, the z-score "tells us" the distance from the population mean, and in this case this value equals zero:  

[tex] \\ x = \mu[/tex]

Therefore

[tex] \\ z = 0[/tex]

So, the value 155 is zero standard deviations from the [population] mean.

Complete Question

From the mid-1960's to the early 1990's, there was a slow but steady decline in SAT scores. For example, take the Verbal SAT. The average in 1967 was about 543; by 1994, the average was down to about 499. However, the SD stayed close to 110. The drop in average has a large effect on the tails of the distribution.

Estimate the percentage of students scoring over 700 on 1967.

A 0.7%

B  7%

C 7.67%

D 7.6%

Answer:

The correct option is D

Step-by-step explanation:

From the question we are told that

   The average  SAT score in 1967 is  [tex]\= x_1 =543[/tex]

     The  standard deviation of score in 1967 is  [tex]\sigma_ 1= 110[/tex]

     The average  SAT score in 1994 is  [tex]\= x_2 = 499[/tex]

      The  standard deviation of score in 1967 is  [tex]\sigma_ 2 = 110[/tex]

The percentage of students scoring over 700 on 1967 is mathematically represented as

   [tex]P(X > 700)[/tex]

Where X is the random variable representing score of student above 700

Now  normalizing the above probability we have

     [tex]P(X > 700) = P(Z > \frac{700 - \= x_1 }{\sigma } )[/tex]

substituting values

      [tex]= P(Z > \frac{700 - \= 543}{110 } )[/tex]

      [tex]= P(Z > 1.83 )[/tex]

Form the normalized z table  

      =  0.076

     =  7.6 %

Answer:

3a) 30% more than original price

b) 70% of the original price

c) 17times the original price

d) 70% less than original price

e) t + 0.85t

f) t - 0.15t

g) t - 0.85t

h) t + 0.15t

4. The expression that can be used to find the amount of money in his bank = m + 0.25m

Question:

3. Match each statement with an expression that could be used to find the price.

'The expressions for a to d were not stated in the question'.

a) p+ 0.3p

b) 0.7p

c) 17p

d) p-07p

'From e to h, we were not told what to determine'.

Write the expression in terms of time

e. 85% more than the original time

f. 15% less time than the original

g. 85% time decrease

h. 15% time increase

4. Ronnie increased the amount of money in his piggy bank by 25%. Which expression can be used to find the amount of money in his bank? Let "m" represent the original​.

Step-by-step explanation:

let original price = p

a) p+ 0.3p = p + 30% of p

30% more than original price

b) 0.7p = 70% of p

= 70% of the original price

c) 17p = 17 × p

= 17times of the original price

d) p-0.7p = p - 70% of p

= 70% less than original price

Let original time = t

e) 85% more than the original time = t + 85%of t

= t + 0.85t

f) 15% less time than the original time = t - 15% of t

= t - 0.15t

g) 85% time decrease = t - 85% of t

= t - 0.85t

h) 15% time increase = t + 15% of t

= t + 0.15t

4. Since "m" represent the original amount in Hus piggy bank

An increase of 25% = original amount + 25% of original amount

= m + 25% of m

'Of' means multiplication

= m + 0.25 ×m

= m + 0.25m

= 1.25m

The expression that can be used to find the amount of money in his bank = m + 0.25m

easy claps!!

Answer: 30=2x+4 and there are 17 girls in the class.

Step-by-step explanation: if x+4=[total girls] and x=[total boys] and 30=[total kids], then x+4+x = 2x+4 = [total kids], since total kids id 30 then our equation is 30 = 2x + 4 and x= 13boys so 30-13= 17girls.

It's BASIC prealgebra so you should probably practice bit more with linear equations!

Answer:

x = -8 or x = 3

Step-by-step explanation:

To factor ax² + bx + c, use AC method.

a times c is 1 × -24 = -24.

Factors of ac (-24) that add up to b (5) are 8 and -3.

Divide by a and reduce: 8/1 and -3/1.

Therefore, the factors are x + 8 and x − 3.

x² + 5x − 24 = 0

(x + 8) (x − 3) = 0

x = -8 or 3

Answer:

The standard unemployment rate is of 0.0794 = 7.94%.

Step-by-step explanation:

The standard unemployment rate, as a proportion, is the number of unemployed people divided by the size of the labor force.

In this question:

Labor force: 189 million

Number of unemployed people: 15 million

What is the standard unemployment rate?

15/189 = 0.0794

The standard unemployment rate is of 0.0794 = 7.94%.

Answer:

You can't find the next solution without more information.

Step-by-step explanation:

Answer:

8 hours

Step-by-step explanation:

Solve with a proportion

[tex]\frac{12}{5}[/tex] = [tex]\frac{19.20}{x}[/tex]

Multiply 5 by 1.6 to get x

5 x 1.6 = 8

Answer:

28 and 32

Step-by-step explanation:

they have the most

Answer:

B. Average of the data set

Step-by-step explanation:

The mean is defined as the average of a data set and it's formula is

Mean = [tex]\frac{sum of observations}{number of observations}[/tex]

Answer:

1<X<=6

Step-by-step explanation:

seven less than six times her number is between negative one and twenty-nine (inclusive).

The above statement can be expressed mathematically thus;

Let the number be x

6x-7= (-1 ,29]

Hence 6x-7 = -1=>6x=6=>x=1 or

6x-7= 29=>6x=36=>x=6

Hence 1<X<=6

Answer:

B.

Step-by-step explanation:

A cone with a radius of 1-unit will be obtained by rotating the 3-D figure.

Answer:

15 baskets

Step-by-step explanation:

Answer:

746 mi^2

Step-by-step explanation:

The top rectangle has an area of

A = 22*23 =506

The bottom rectangle has an area of

A =10 *24 = 240

Add the areas together

506+ 240 =746

Answer:

746

Step-by-step explanation:

22*23= 506

24*10= 240

506+240= 746

plz mark brainliest

Answer:

Step-by-step explanation:

The given equations are

x + y = 6- - - - - - - - -1

y + z = 6- - - - - - - -2

x + z = 6- - - - - - - - - 3

From equation 2, y = 6 - z

Substituting y = 6 - z into equation 1, it becomes

x + 6 - z = 6

x - z = 6 - 6

x - z = 0

x = z

Substituting x = z into equation 3, it becomes

z + z = 6

2z = 6

z = 6/2

z = 3

x = 3

Substituting x = 3 into equation 1, it becomes

3 + y = 6

y = 6 - 3

y = 3

ax + by + cz = 0

3a + 3b + 3c = 0

3(a + b + c) = 0

Therefore, it is impossible

Answer:

a) 5/9

b) 1/3

Step-by-step explanation:

a) P(Die A or Die B) = P(red and red with Die A) + P(red and red with Die B)

                               = 4/6 × 4/6 +  2/6×2/6

                               = 5/9

b)  P(Die A or Die B) = P(red and red and red with Die A) + P(red and red and red with die B)

                           = 4/6×4/6×4/6 + 2/6×2/6×2/6

                          = 1/3

Answer:

ITS C

Step-by-step explanation:

The other answer is wrong, I just tried it.

Answer:

It's C on EDG

Step-by-step explanation:

            ∠FGK and ∠FGH               Im pretty sure its right

A ray is a half-infinite line. The pairs of non-overlapping angles that share a ray to make a right angle are ∠FGE and ∠FGH.

A half-infinite line (also known as a half-line) with one of the two points and is commonly used to represent a ray. It is assumed to be infinite.

A straight line has an angle of measurement of 180°. And a 90° angle is made when two lines are perpendicular to each other.

As we can see the line EGH is a straight line, and FG is another line that is perpendicular to line EH, therefore, it will form two angles measuring 90°. These angles will be ∠FGE and ∠FGH.

Hence, the pairs of non-overlapping angles that share a ray to make a right angle are ∠FGE and ∠FGH.

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