From the solution to the question that we have here, the answer is A. There is no solid proof that the number of hours worked dropped after the income rise.
Let μ be the population mean number of hours worked per week by teachers who work part-time jobs, after the salary increase. Here are the alternate and null hypotheses:
H0: μ = 13
H1: μ < 13
n = 400
[tex]\bar{X}=12.5[/tex]
μ = 13
Formula for the t-test statistics is
[tex]t = \frac{\bar{X}-\mu}{s/\sqrt{n} }[/tex]
t = (12.5 - 13)/(6.5/√400)
t = (- 0.5)/(6.5/20)
t = - 10/6.5
= -1.5388
Degree of freedom is 400 -1 = 399
α = 0.05
The p-value is p(t < -1.5385) = 0.062
The p-value exceeds the level of significance. Therefore, we unable to reject the null hypothesis.
Hence, option a is correct.
Learn more on statistics here:
brainly.com/question/19243813
#SPJ4
A sample size a 28 produced test statistic is T equals 2. 51
The mathematical probabilities of p values lies between range from 0 to 1 and using technology, p-value is 0.050086.
Sample = n = 28.
t = 2.051
P value by the means of the technology is 0.050086.
The likelihood of receiving outcomes from a statistical hypothesis test that are at least as severe as the actual results, provided the null hypothesis is true, is known as the p-value in statistics. The p-value provides the minimal level of significance at which the null hypothesis would be rejected as an alternative to rejection points. The alternative hypothesis is more likely to be supported by greater evidence when the p-value is lower.
P-value is frequently utilised by government organisations to increase the credibility of their research or reports. The U.S. Census Bureau, for instance, mandates that any analysis with a p-value higher than 0.10 be accompanied by a statement stating that the difference is not statistically significant from zero.
Learn more about P-value:
https://brainly.com/question/13786078
#SPJ4
Complete question:
A significance test was performed to test H o : u = 2 versus the alternative He: u # 2. A sample of size 28 produced a standardized test statistic of t = 2.051. Assume all conditions for inference are met. Using Table B, the P-value falls between and . (Do not round) Using technology the P-value is . (Round to 4 decimal places)
At a high school with 900 total students, the true opinions of the entire student body on whether they approve of the student council president are shown below. Follow the directions below to determine a confidence interval for a sample of size 109.
Based on the above, the proportion of the population who said yes is 78%.
What is the Population size?To be able to calculate the population proportion who said yes, you have to divide the number of students who said "Yes" by the total amount or number of students in the whole population:
Hence it will be:
Population proportion who said yes = 741/950
= 0.78
= 78%
So, the proportion of the population who said yes is 0.78 or 78%.
Learn more about Population from
https://brainly.com/question/29885712
#SPJ1
See text below
At a high school with 950 total students, the true opinions of the entire student body on whether they approve of the student council president are shown below. Follow the directions below to determine a confidence interval for a sample of size 125.
Population Yes 741, Population No 209, Population Size 950
Population proportion who said yes: ---
Deriving the Law of Cosines
Try it
Follow these steps to derive the law of cosines.
✓ 1. The relationship between the side lengths in AABD is
C2 = x2 +hby the Pythagorean theorem M
✓ 2. The relationship between the side lengths in ACBD is
Q2 = (b - x)2 +hby the Pythagorean theorem
V 3. The equation e? = (6 – x)2 + h? is expanded y to become
22 = 62 - 2x + x2 +h?
a
h
✓ 4. Using the equation from step 1, the equation
22 = 62 - 2bx +32+ hbecomes a = 62 - 2bx + 2
by substitution
A
х
D
b-x
С
Correct! You have completed this exercise.
b
1) The relationship between the side lengths in ΔABD is c² = x² + h² by the Pythagorean Theorem.
2) . The relationship between the side lengths in Δ CBD is a² = (b-x)² + h² by the Pythagorean Theorem.
3) The expanded equation is e² = x² -12x + 36 + h²
4) the expanded equation is a² = b²-x²+32
According to the Pythagorean theorem, the square of the hypotenuse (c) of a right triangle equals the sum of the squares of the other two sides (a² + b²).
So
1) The relationship between the side lengths in ΔABD is c² = x² + h² by the Pythagorean Theorem.
2) The relationship between the side lengths in Δ CBD is a² = (b-x)² + h² by the Pythagorean Theorem.
3) The equation is e² = (6 - x)² + h² when expanded
e² = 36 - 12x + x² + h²
or
e² = x² -12x + 36 + h²
4) Using this equation, we can solve for h² by subtracting (b-x)² from both sides:
a² - (b-x)² = h²
Now we can substitute this expression for h² into the equation given in step 3
2² = 6² - 2bx + (a² - (b-x)²)
Simplifying this equation, we get:
4 = 36 - 2bx + a² - (b-x)²
Expanding the square term, we get:
4 = 36 - 2bx + a² - (b² - 2bx + x²)
Simplifying further, we get:
4 = 36 - b² + x² + a²
Rearranging, we get:
a² = b² - x² + 32
So the equation expanded is a² = b² - x² + 32.
Learn more about Pythagorean theorem:
https://brainly.com/question/14930619
#SPJ4
Full Question:
For 1 and 2, see attached image.
3) The equation e²= (6 – x)² + h² is expanded y to become ?
4) Using the equation from step 1, the equation
2² = 6² - 2bx +32+ h becomes a = 62 - 2bx + 2
by substitution
22 = 62 - 2x + x2 +h?
La o florarie s-au adus ghivece de flori.in prima zi s-a vandut 1 supra 2 din numarul ghivecelor,a doua zi 1 supra 4 din numarul ramas si inca 7 ghivece iar a treia zi restul de 20 de ghivece.cate ghivece s-au vandut in fiecare zi si cate sau adus initial la florarie
S-au adus initial 68 de ghivece de flori, iar în fiecare zi s-au vândut, respectiv, 34, 17 și 17 ghivece.
Initial, la florărie s-au adus x ghivece de flori. În prima zi s-au vândut 1/2 * x ghivece. A doua zi, din numărul rămas s-au vândut 1/4 * (x - 1/2 * x) ghivece, adică 1/4 * 1/2 * x.
În plus față de acestea, s-au vândut încă 7 ghivece, deci în total în a doua zi s-au vândut 1/4 * 1/2 * x + 7 ghivece. În a treia zi s-au vândut restul de 20 de ghivece, deci numărul rămas la finalul celei de-a doua zile este x - 1/2 * x - 1/4 * 1/2 * x - 7. Trebuie să fie egal cu 20, deci avem ecuația x - 1/2 * x - 1/4 * 1/2 * x - 7 = 20.
Rezolvând această ecuație, obținem x = 128. Prin urmare, în prima zi s-au vândut 1/2 * 128 = 64 ghivece, în a doua zi s-au vândut 1/4 * 1/2 * 128 + 7 = 15 ghivece, iar în a treia zi s-au vândut restul, adică 20 ghivece.
Learn more about x
brainly.com/question/9248395
#SPJ11
Find the sum of the series: 5 2 (K _2k) k=4 5 2 (K2-2k) = k=4
To find the sum of the series given, we need to evaluate the expression for each value of k from 4 to 5 and then add the results together. The expression is 2(K²- 2K). Let's calculate the sum:
For k = 4:
2(4² - 2*4) = 2(16 - 8) = 2(8) = 16
For k = 5:
2(5² - 2*5) = 2(25 - 10) = 2(15) = 30
Now, we add the results together:
Sum = 16 + 30 = 46
So, the sum of the series is 46.
In mathematics, a sum of a series refers to the total value obtained by adding up the terms of a sequence. A series is a sum of an infinite number of terms or a sum of a finite number of terms.
For example, the sum of the series 1 + 2 + 3 + 4 + 5 is:
1 + 2 + 3 + 4 + 5 = 15
The sum of the series can be found using different methods depending on the type of series. For example, if the series is an arithmetic series, which means each term is obtained by adding a constant difference to the previous term, we can use the formula:
Sn = n/2 [2a + (n - 1)d]
Where Sn is the sum of the first n terms of the series, a is the first term, d is the common difference, and n is the number of terms in the series.
If the series is a geometric series, which means each term is obtained by multiplying the previous term by a constant ratio, we can use the formula:
Sn = a(1 - r^n) / (1 - r)
Where Sn is the sum of the first n terms of the series, a is the first term, r is the common ratio, and n is the number of terms in the series.
Visit here to learn more about series brainly.com/question/15415793
#SPJ11
Susan set up a lemonade stand to raise money for a children's hospital. She's selling cups of lemonade for $2. 50 each and brownies for $1. 50 each. She sells 280 items and raises $540.
How much money does Susan raise from selling lemonade?
If she sells 280 items and raises $540, then Susan raises $300 from selling lemonade.
To determine how much money Susan raises from selling lemonade, we'll set up a system of equations using the given information.
Let x be the number of lemonade cups and y be the number of brownies sold. We know:
1. x + y = 280 (total items sold)
2. 2.50x + 1.50y = 540 (total money raised)
First, we'll solve for x in equation 1:
x = 280 - y
Now, substitute this expression for x in equation 2:
2.50(280 - y) + 1.50y = 540
Simplify and solve for y:
700 - 2.50y + 1.50y = 540
-1.00y = -160
y = 160
Now that we have the number of brownies (y), we can find the number of lemonade cups (x):
x = 280 - 160
x = 120
Finally, calculate the money Susan raises from selling lemonade:
Money from lemonade = 120 * $2.50 = $300
So, Susan raises $300 from selling lemonade.
More on selling: https://brainly.com/question/29250593
#SPJ11
Which polynomial does the model represent? The model shows 1 black square block, 2 white thin blocks, 1 black thin block, 1 white small square block, 3 black small blocks
The polynomial represented by the model is [tex]]x^2 - x + 2[/tex]
Based on the provided model, the polynomial represented is:
1 black square block: x^2
2 white thin blocks: -2x
1 black thin block: x
1 white small square block: -1
3 black small blocks: +3
The polynomial that the model represents is:
[tex]x^2 - 2x + x - 1 + 3[/tex]
Combining like terms, we get:
[tex]x^2 - x + 2[/tex]
So, the polynomial represented by the model is [tex]x^2 - x + 2[/tex].
To know more about "Polynomial" refer here:
https://brainly.com/question/20121808#
#SPJ11
How would the equation for the blade of the wind turbine change if the point starts at the π2
position?
If the point starts at the π/2 position, the equation for the blade of the wind turbine will be sin(θ + π/2) = sin(θ - π/2)cos(β) + cos(θ - π/2)sin(β).
The equation for the blade of the wind turbine is given by the expression sin(θ) = sin(θ - β)cos(α) + cos(θ - β)sin(α), where θ represents the angle of the blade, β represents the angle between the wind direction and the blade, and α represents the pitch angle of the blade.
If the point starts at the π/2 position, we need to substitute θ + π/2 for θ in the equation. This gives us sin(θ + π/2) = sin(θ - β + π/2)cos(α) + cos(θ - β + π/2)sin(α).
Using trigonometric identities, we can simplify this expression to sin(θ + π/2) = cos(θ - β)cos(α) - sin(θ - β)sin(α).
Finally, substituting β for (π/2 - β) in the above equation, we get sin(θ + π/2) = sin(θ - π/2)cos(β) + cos(θ - π/2)sin(β). This is the required equation for the blade of the wind turbine if the point starts at the π/2 position.
For more questions like Equation click the link below:
https://brainly.com/question/16663279
#SPJ11
Write an equation for the circle graphed below.
-4
-2
6
4
2
-2
-4
-6
2
Answer:
[tex]\left(x\:+\:1\right)^2\:+\:y^2=25[/tex]
Step-by-step explanation:
The equation of a circle with radius r and center at (a, b) is given by
(x - a)² + (y - b)² = r²
Let's first find the radius
The circle intersects the x axis at two points (-6, 0) and (4, 0)
The diameter is therefore the absolute difference between the x values:
|-6 - 4| same as |4 - (-6)| = 10
The radius r = 5 (half of diameter)
Now, let's find the center point of the circle. This will lie midway between (-6, 0) and (4, 0)
Midpoint (xm, ym) between two points(x1, y) and (x2, y2) :
xm = (x1 + x2)/2 = (-6 + 4)/2 = -1
ym = (y1 + y2)/2 = (0 + 0)/2 = 0
So the center (a, b) = (-1, 0) with a = -1, b = 0
The equation of the circle therefore is
(x - a)² + (y - b)² = r²
( x - (-1) )² + (y - 0)² = 25
(x + 1)² + y² = 25
To find a and b take any point (x, y) and plug these
Which function is a parabola?
F(x)=5-x^2
X - 2 -1 -0 0 3
G(x) 3 0 -1 0 3
1. F(x) only
2. G(x) only
3. Both f(x) and g(x)
4.neither
Answer:
1. F(x) only-----------------------
F(x) is in the format of a quadratic function:
y = ax² + bx + c, with a = - 1, b = 0, c = 5Hence it is a parabola.
The table represents a relation with two x-intercepts and two y-intercepts (points with the coordinate of 0).
We know that parabola can have maximum of one y-intercept, hence G(x) is not a parabola.
The matching answer choice is the first one.
Which expression is represented by the number line?
A number line going from negative 4 to positive 4. An arrow goes from negative 2. 5 to negative 1, from 0 to 3, and from 3 to negative 2. 5
The expression represented by the given number line is f(x) = -k(x+2.5)(x-3) where k > 0.
The expression represented by the given number line can be determined by identifying the values that correspond to the endpoints of each arrow and the direction of the arrow.
Starting from the left endpoint, the arrow goes from -2.5 to -1. This means that the expression is positive between -2.5 and -1. To determine the exact expression, we need to know the interval of the arrow.
The arrow starts at 0 and ends at 3, which means the expression is positive between 0 and 3. Finally, the arrow goes from 3 to -2.5, which means the expression is negative between 3 and -2.5.
Putting all of this information together, we can write the expression as:
f(x) = k(x+2.5)(x-3)
where k is a constant that determines the overall scale of the expression. Since the expression is positive between -2.5 and -1, we know that k must be negative. Since the expression is negative between 3 and -2.5, we know that k must be positive.
Therefore, the expression represented by the given number line is:
f(x) = -k(x+2.5)(x-3) where k > 0.
To learn more about expression click on,
https://brainly.com/question/5503202
#SPJ4
how many different homotheties can one of two concentric circles be projected onto the other?
Answer: If two concentric circles are projected onto each other, then there is only one homothety that maps one circle onto the other. This is because the center of the circles is the only point that remains fixed under the homothety.
The radius of a circle measures 7 inches. A central angle of the circle measuring 4π15 radians cuts off a sector.
What is the area of the sector?
Enter your answer, as a simplified fraction
The area of sector is 14π/3 square inches for a circle having a radius of 7 inches and measures an angle of 4π/15 radians.
Radius of circle = 7 inches
Angle of circle = 4π/15 radians
The area of a sector of a circle can be calculated by using the formula:
A = (θ/2) × [tex]r^2[/tex]
A = The area of the sector
θ = central angle in radians
r = radius of the circle.
Substituting the given values in the formula:
Area = (θ/2) × [tex]r^2[/tex]
Area = (4π/15 × 1/2) × [tex]7^2[/tex]
Area= (2π/15) × 49
Area = 14π/3
Therefore, we can conclude that the area of the sector is 14π/3 square inches.
To learn more about the Area of the Sector
https://brainly.com/question/1582027
#SPJ4
And 7/8 hours Greg reads 2/3 chapters what’s the unit rate in chapters per hour?
The unit rate in chapters per hour is 21/16 hours
How to calculate the unit rate?Greg read 7/8 hours in 2/3 chapter
The unit rate can be calculated as follows
7/8= 2/3
1= x
cross multiply both sides
2/3x= 7/8
x= 7/8 ÷ 2/3
x= 7/8 × 3/2
x= 21/16
Hence 21/16 chapters is read in one hour
Read more on unit rate here
https://brainly.com/question/29216013
#SPJ1
Homework
Saved
Quail Company is considering buying a food truck that will yield net cash inflows of $11,000 per year for seven years. The truck costs
$45,000 and has an estimated $6,700 salvage value at the end of the seventh year. (PV of $1, FV of $1. PVA of $1, and FVA of $1) (Use
appropriate factor(s) from the tables provided. Enter negative net present values, if any, as negative values. Round your present
value factor to 4 decimals. )
What is the net present value of this investment assuming a required 8% return?
Net Cash Flows x PV Factor
$
Years 1-7
'Year 7 salvage
Totals
11,000
6,700
Present Value of
Net Cash Flows
$
0
3,909
$
0. 58351 =
11
Initial investment
45,000
Net present value
The net present value of this investment, assuming a required 8% return, is approximately $13,829.
To calculate the net present value (NPV) of this investment, we'll first find the present value of the net cash flows and the salvage value, then subtract the initial investment.
For the net cash flows, we'll use the Present Value of Annuity (PVA) formula:
PVA = Net Cash Flow * [(1 - (1 + r)^(-n)) / r]
Where:
- Net Cash Flow is $11,000
- r is the required return (0.08)
- n is the number of years (7)
PVA = 11,000 * [(1 - (1 + 0.08)^(-7)) / 0.08]
PVA = 11,000 * 4.99271
PVA ≈ $54,920
Next, we'll find the present value of the salvage value at the end of year 7:
PV_salvage = Salvage Value / (1 + r)^n
PV_salvage = 6,700 / (1 + 0.08)^7
PV_salvage ≈ $3,909
Now, we can calculate the NPV by adding the present values and subtracting the initial investment:
NPV = (PVA + PV_salvage) - Initial Investment
NPV = (54,920 + 3,909) - 45,000
NPV ≈ $13,829
The net present value of this investment, assuming a required 8% return, is approximately $13,829.
To learn more about annuity, refer below:
https://brainly.com/question/23554766
#SPJ11
suppose 44% of the doctors in a hospital are surgeons. if a sample of 738 doctors is selected, what is the probability that the sample proportion of surgeons will differ from the population proportion by more than 4% ? round your answer to four decimal places.
The probability of the the sample proportion of surgeons will be given as 1.
The z-score is a dimensionless variable that is used to express the signed, fractional number of standard deviations by which an event is above the mean value being measured. It is also known as the standard score, z-value, and normal score, among other terms. Z-scores are positive for values above the mean and negative for those below the mean.
For this case we can define the population proportion p as "true proportion of surgeons" and we can check if we can use the normal approximation for the distribution of p,
1) np = 738 x 0.44 = 324.72 > 10
2) n(1 - p) = 738 x (1 - 0.44) = 413.28 > 10
3) Random sample: We assume that the data comes from a random sample Since we can use the normal approximation the distribution for P is given by:
psimN(p,[tex]\sqrt{\frac{p(1-p)}{n} }[/tex])
With the following parameters:
Hp = 0.44
[tex]\sigma_p=\sqrt{\frac{0.44(1-0.44)}{738} }[/tex]
= 0.01827
And we want to find this probability:
P(p > 0.04)
And we can use the z score formula given by:
[tex]z=\frac{p-\mu}{\sigma}[/tex]
And if we calculate the z score for p = 0.39 we got:
[tex]z=\frac{0.04-0.44}{0.01827}[/tex] = -21.893
And we can find this probability using the complement rule and the normal standard table or excel and we got:
P(p > 0.04) = P(Z > -21.893) = 1 − P(Z < −21.893) = 1 - 0 = 1.
Learn more about Probability:
https://brainly.com/question/30859510
#SPJ4
Mrs. Rambo got a YMCA membership for her family. The pass has a onetime fee of $30 and then $5 for every visit to the YMCA. Her bill the first month was $150. How many times did her family visit the YMCA?
They visited ------------- times last month. Way to go Rambo family!
Answer:
Step-by-step explanation: Solution:
Total cost: 150
150-30=120
120 divided by 5 = 24
They visited 24 times in a month.
helpppp me please hurehshsh
Answer:
m∠W = 45°
Step-by-step explanation:
When both legs of a right triangle are congruent, we know that it is an isosceles right triangle because of the isosceles triangle theorem.
Therefore, we can identify W as:
m∠W = (180 - 90)° / 2
m∠W = 45°
Note: We get the / 2 from the fact that both non-right angles are congruent; therefore, they are half of the remaining angle measures after subtracting the right angle (90°) from the total of a triangle (180°).
There were 16 boys and 12 girls at a soccer camp. The director wanted to make teams with the same number of boys and girls on each team. The greatest number of teams the director could make is --------. There will be ------ girls on each team
The greatest number of teams the director could make is 4, and there will be 3 girls on each team.
Since the director wants to make teams with an equal number of boys and girls, the number of teams must be a factor of both 16 and 12. The common factors of 16 and 12 are 1, 2, 4, and 8. Since the director wants to make as many teams as possible, the greatest number of teams is 4.
Each team will have 4 boys and 3 girls, so the total number of girls needed is 4 x 3 = 12. Since there are 12 girls in the camp, there will be 12/4 = 3 girls on each team. Therefore, the greatest number of teams the director could make is 4, and there will be 3 girls on each team.
For more questions like Teams click the link below:
https://brainly.com/question/10750297
#SPJ11
Question 3 B0/5 pts 100 Details If the eighth term of a geometric sequence is 81920, and the eleventh term of an geometric sequence is 5242880 its first term a and its common ratio r = Question Help:
To find the first term and common ratio of a geometric sequence, we can use the formula for the nth term:
a_n = a_1 * r^(n-1)
We are given the eighth and eleventh terms, so we can set up two equations:
a_8 = a_1 * r^(8-1) = 81920
a_11 = a_1 * r^(11-1) = 5242880
After dividing the second with by the first equation, we get:
(a_1 * r^(11-1)) / (a_1 * r^(8-1)) = 5242880 / 81920
Simplifying, we get:
r³ = 64
Doing the root of cube both sides, we get:
r = 4
Substituting this into the first equation, we get:
a_1 * 4^(8-1) = 81920
a_1 * 4^7 = 81920
a_1 = 5
Therefore, the first term is 5 and the common ratio is 4.
In a geometric sequence, each term is obtained by multiplying the previous term by a constant factor called the common ratio (r). The formula for the nth term of a geometric sequence is:
an = a * r^(n-1)
Given that the 8th term (a8) is 81,920 and the 11th term (a11) is 5,242,880, we can set up the following equations:
81920 = a * r^(8-1) => 81920 = a * r⁷ (1)
5242880 = a * r^(11-1) => 5242880 = a * r¹⁰ (2)
Now, we need to find the values of a (the first term) and r (the common ratio). Divide equation (2) by equation (1):
(5242880 / 81920) = (a * r¹⁰) / (a * r⁷)
64 = r^3
Now, we can find the common ratio r:
r = 4 (since 4³ = 64)
Next, substitute r back into equation (1) to find the first term a:
81920 = a * 4⁷
a = 81920 / 16384
a = 5
So, the first term (a) is 5, and the common ratio (r) is 4.
Visit here to learn more about geometric sequence brainly.com/question/13008517
#SPJ11
Can you help me do 1+1
Answer:
The answer to 1+1 is 2.
Answer:
2
Step-by-step explanation:
White shapes are black shapes are used in a game.
Some of the shapes are circles.
All the other shapes are squares.
The ratio of the number of white shapes to the number of black shapes is 7:3
The ratio of the number of white circles to the number of white squares is 2:7
The ratio of the number of black circles to the number of black squares is 1:2
Work out what fraction of all the shapes are circles.
Give your answer as a fraction in its simplest form.
Fernando fue a comprar entradas para que él y
sus 7 amigos asistan a la Expo-Loncoche que
se realiza en La ciudad del mismo nombre.
Entre todos lograron reunir $14. 000, pero cada
entrada cuesta $ 3. 600 ¿Cuánto dinero le falta
a cada uno para comprar las entradas?
After evaluation each person is missing $1400 to purchase the tickets to enter the Expo-Loncoche that takes place in the city.
Then, the count of individuals multiplied by the price per ticket yields the total cost of the tickets. So we have to apply principles of algebraic expression.
Now, in order to solve the problem, we can first find the total cost of tickets, which is $25,200
(7 friends + Fernando = 8 people × $3,600 = $28,800).
The whole cost can then be deducted from the total amount raised,
$14,000 - $25,200 = -$11,200.
Therefore, they are short $11,200 in total.
Finally, we have to divide that sum by the required number of tickets, which is 8,
-$11,200 8 = -$1,400.
Hence, each person needs an additional $1,400 to buy tickets.
To learn more about algebraic expression,
https://brainly.com/question/4344214
#SPJ4
The Complete question - Fernando went to buy tickets so that he and his 7 friends attend the Expo-Loncoche that takes place in the city of the same name. Together they managed to raise $14,000, but each the entrance costs $3,600. How much money is missing each to buy tickets?
A random sample of 40 students from each grade level was surveyed regarding their preference for a class field trip. If there are 220 members of the 7th grade class, then how many students can be expected to prefer the zoo?
Answer:
Step-by-step explanation:
We can set up the proportion (20/40) = (x/220), where x is the number of students in the 7th grade class who prefer the zoo. Cross-multiplying this proportion gives us 40x = 20*220, which simplifies to x = 110.
Therefore, we can expect that 110 students in the 7th grade class prefer the zoo.
To explain this solution in more detail, we can use the concept of proportionality. In statistics, when we take a random sample from a larger population, we can use the proportion of the sample to estimate the proportion of the population.
If we assume that the sample is representative of the population, then the proportion of students who prefer the zoo in the sample should be similar to the proportion of students who prefer the zoo in the 7th grade class.
By setting up a proportion between the sample and the population, we can estimate the number of students in the 7th grade class who prefer the zoo. We know that 20 out of the 40 students in the sample from the 7th grade class prefer the zoo,
so we can use this proportion to estimate the number of students in the 7th grade class who prefer the zoo. Cross-multiplying the proportion gives us the equation 40x = 20*220, which we can solve for x to get x = 110.
It is important to note that this is just an estimate and that there is some degree of uncertainty involved in the estimation process. However, by using statistical methods such as proportionality, we can obtain a reasonable estimate that can help us make informed decisions.
To know more about proportion refer here:
https://brainly.com/question/31548894#
#SPJ11
Marcus is responsible for maintaining the swimming pool in his community. He adds chemicals, when needed, to lower the pH of the pool.
-The maximum pH value allowed for the pool is 7. 8.
-The pool currently has a pH value of 6. 9.
-The pH value of the pool increases by 0. 05 per hour.
Write an inequality that can be used to determine x, the number of hours before Marcus will need to add chemicals to maintain the pH for the pool
An inequality that can be used to determine x, the number of hours before Marcus will need to add chemicals to maintain the pH for the pool would be 6.9 + 0.05x ≤ 7.8
To determine the number of hours (x) before Marcus will need to add chemicals to maintain the pool's pH, we can use an inequality with the given information.
-The maximum pH value allowed for the pool is 7.8.
-The pool currently has a pH value of 6.9.
-The pH value of the pool increases by 0.05 per hour.
The inequality for this scenario would be:
6.9 + 0.05x ≤ 7.8
This inequality states that the current pH value (6.9) plus the increase in pH per hour (0.05x) should be less than or equal to the maximum allowed pH value (7.8). This will help us determine the number of hours (x) before Marcus needs to add chemicals to maintain the pH for the pool.
To know more about inequality refer here:
https://brainly.com/question/30228778
#SPJ11
suppose that 0.4% of a given population has a particular disease. a diagnostic test returns positive with probability .99 for someone who has the disease and returns negative with probability 0.97 for someone who does not have the disease. (a) (10 points) if a person is chosen at random, the test is administered, and the person tests positive, what is the probability that this person has the disease? simplify your answe
The probability that a person has a disease given that they test positive, when 0.4% of the population has the disease and the test is positive with probability 0.99 if they have the disease and 0.03 if they don't have it, is 0.116 or about 11.6%.
Let D be the event that the person has the disease and T be the event that the person tests positive. We need to calculate P(D|T), the probability that the person has the disease given that they test positive.
Using Bayes' theorem, we have
P(D|T) = P(T|D) * P(D) / P(T)
where P(T|D) is the probability of testing positive given that the person has the disease, P(D) is the prior probability of having the disease, and P(T) is the total probability of testing positive, which can be calculated as
P(T) = P(T|D) * P(D) + P(T|D') * P(D')
where P(T|D') is the probability of testing positive given that the person does not have the disease, and P(D') is the complement of P(D), which is the probability of not having the disease.
Substituting the given values, we get
P(D|T) = (0.99 * 0.004) / [(0.99 * 0.004) + (0.03 * 0.996)]
= 0.116
Therefore, the probability that the person has the disease given that they test positive is 0.116 or about 11.6%.
To know more about Probability:
https://brainly.com/question/11234923
#SPJ4
A windshield wiper is 45 cm long and
creates a central angle of 120° in one
wipe. what is the sector area?
The windshield sector area is 706.86 cm².
To calculate the sector area of the windshield wiper, we need to use the formula for the area of a sector of a circle. The formula is:
A = (θ/360°) x πr²
where A is the area of the sector, θ is the central angle of the sector in degrees, and r is the radius of the circle.
In this problem, we are given that the windshield wiper has a length of 45 cm, which means that the radius of the circle traced by the wiper is 45 cm/2 = 22.5 cm.
We are also given that the wiper creates a central angle of 120° in one wipe. Substituting these values into the formula, we get:
A = (120°/360°) x π(22.5 cm)²
A = (1/3) x π x (22.5 cm)²
A ≈ 706.86 cm²
Therefore, the sector area of the windshield wiper is approximately 706.86 square centimeters.
To learn more about sector area refer here:
https://brainly.com/question/16367606
#SPJ11
8-70. Assume Figure A and Figure B, at right, are similar. Homework Help
a. If the ratio of similarity is (3)/(4), then what is the ratio of the perimeters of Figures A and B ?
b. If the perimeter of Figure A is p and the linear scale factor is r, what is the perimeter of Figure B?
c. If the area of Figure A is a and the linear scale factor is r, what is the area of Figure B?
a. The ratio of the perimeters of Figures A and B will also be (3)÷(4).
b. This is because the corresponding sides of Figure B are (3÷4) is smaller than those of Figure A, and the perimeter is the sum of all the sides.
c. The area of Figure B will be (9÷16)a.
What is perimeter ?Perimeter refers to the total length of the boundary or the outer edge of a two-dimensional closed shape. It is the sum of the lengths of all sides of the shape.
a. Since the ratio of similarity is (3)÷(4), this means that the corresponding sides of Figure A and Figure B are in the ratio of (3)÷(4). Therefore, the ratio of the perimeters of Figures A and B will also be (3)÷(4).
b. If the perimeter of Figure A is p and the linear scale factor is r, then the perimeter of Figure B will be (3÷4)p. This is because the corresponding sides of Figure B are (3÷4) is smaller than those of Figure A, and the perimeter is the sum of all the sides.
c. If the area of Figure A is a and the linear scale factor is r, then the area of Figure B will be (3÷4) square times smaller than that of Figure A. This is because the area of a similar figure proportional to the square of the linear scale factor.
Therefore, the area of Figure B will be (9÷16)a.
To learn more about Perimeter from given link.
brainly.com/question/27591380
#SPJ1
THIS IS DUE TONIGHT! PLEASE HELP ME! :c
USE STRUCTURE Complete the table to show the effect that the transformation has on the table of the parent function f(x)=x2.
g(x)is a reflection of f(x)across the x-axis.
x f(x) g(x)
-2 4
-1 1
0 0
1 1
2 4
The table of values to show the effect of the transformation is
x f(x) g(x)
-2 4 -4
-1 1 -1
0 0 0
1 1 -1
2 4 -4
Completing the table of values to show the effectFrom the question, we have the following parameters that can be used in our computation:
f(x) = x²
Also, we have
g(x) is a reflection of f(x)across the x-axis
This means that
g(x) = -f(x)
So, we have
g(x) = -x²
Using the above as a guide, we have the following:
x f(x) g(x)
-2 4 -4
-1 1 -1
0 0 0
1 1 -1
2 4 -4
Read more about transformation at
https://brainly.com/question/27224272
#SPJ1
A newspaper for a large city launches a new advertising campaign focusing on the number of digital subscriptions. The equation S(t)=31,500(1. 034)t approximates the number of digital subscriptions S as a function of t months after the launch of the advertising campaign. Determine the statements that interpret the parameters of the function S(t)
The parameters of the function S(t)=31,500(1.034)t are the initial number of digital subscriptions, which is 31,500, and the monthly growth rate, which is 3.4%.
How to find the parameters of the function?
The given function S(t)=31,500(1.034)t is a exponential growth function that models the number of digital subscriptions S as a function of t months after the launch of the advertising campaign. The parameters of the function are the initial number of digital subscriptions, which is 31,500, and the monthly growth rate, which is 3.4%.
The initial value of 31,500 represents the number of digital subscriptions at the start of the advertising campaign. This means that the campaign began with 31,500 digital subscribers.
The monthly growth rate of 3.4% represents the rate at which the number of digital subscriptions is increasing each month due to the advertising campaign. This means that for each month after the launch of the campaign, the number of digital subscribers is increasing by 3.4% of the previous month's total.
For example, after one month, the number of digital subscribers would be:
S(1) = 31,500(1.034)1 = 32,687
After two months, the number of digital subscribers would be:
S(2) = 31,500(1.034)2 = 33,912
And so on...
Therefore, the initial value and monthly growth rate are important parameters that help us understand how the number of digital subscriptions is changing over time due to the advertising campaign.
Learn more about Exponential growth
brainly.com/question/12490064
#SPJ11
