In a large midwestern university (the class of entering freshmen being on the order of 6000 or more students), an SRS of 100 entering freshmen in 1999 found that 20 finished in the bottom third of their high school class. Admission standards at the university were tightened in 1995. In 2001 an SRS of 100 entering freshmen found that 10 finished in the bottom third of their high school class. The proportion of all entering freshmen in 1999 and 2001, who graduated in the bottom third of their high school class, are p1 and p2, respectively.Is there evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced, as a result of the tougher admission standards adopted in 2000, compared to the proportion in 1999? To determine this, you test the hypothesesH0 : p1 = p2 , Ha : p1 > p2.The P-value of your test isA. 0.976.B. 0.024.C. 0.048.D. 0.001.

Answers

Answer 1

Answer:

B. 0.024

The p-value of the test is 0.024 < 0.05(standard significance level), which means that there is enough evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.

Step-by-step explanation:

Before testing the hypothesis, we need to understand the central limit theorem and subtraction of normal variables.

Central Limit Theorem

The Central Limit Theorem establishes 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.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

1999:

Of 100, 20 were in the bottom thid. So

[tex]p_B = \frac{20}{100} = 0.2[/tex]

[tex]s_B = \sqrt{\frac{0.2*0.8}{100}} = 0.04[/tex]

2001:

Of 100, 10 were in the bottom third, so:

[tex]p_A = \frac{10}{100} = 0.1[/tex]

[tex]s_A = \sqrt{\frac{0.1*0.9}{100}} = 0.03[/tex]

To determine this, you test the hypotheses H0 : p1 = p2 , Ha : p1 > p2.

Can also be rewritten as:

[tex]H_0: p_B - p_A = 0[/tex]

[tex]H_1: p_B - p_A > 0[/tex]

The test statistic is:

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

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, and s is the standard error.

0 is tested at the null hypothesis:

This means that [tex]\mu = 0[/tex]

From the sample:

[tex]X = p_B - p_A = 0.2 - 0.1 = 0.1[/tex]

[tex]s_A = \sqrt{s_A^2+s_B^2} = \sqrt{0.03^2+0.04^2} = 0.05[/tex]

Value of the test statistic:

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

[tex]z = \frac{0.1 - 0}{0.05}[/tex]

[tex]z = 2[/tex]

P-value of the test and decision:

The p-value of the test is the probability of finding a difference of proportions of at least 0.1, which is 1 subtracted by the p-value of z = 2.

Looking at the z-table, z = 2 has a p-value of 0.976.

1 - 0.976 = 0.024, so the p-value is given by option B.

The p-value of the test is 0.024 < 0.05(standard significance level), which means that there is enough evidence that the proportion of freshmen who graduated in the bottom third of their high school class in 2001 has been reduced.


Related Questions

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ASAP​

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y = mx+b

y = 1/3x+4

Sincerely,

William

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Step-by-step explanation:

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Step-by-step explanation:

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A red die is tossed and a green die is tossed.what is the probability that a red die shows an even number or the green die shows an even number? Make sure your answer is reduced

Answers

Answer: 75%

Step-by-step explanation:

Since there are 3 even numbers on each die and 3 odd, each dice has a 50% chance of showing an even number.

An easier way to think about this might be what are the chances that both dice show odd, because that is the only scenario where neither show an even number.

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kiyo bought a pizza for 12.75 and four medium drinks to Pauli’s pizza. Define a variable and write an expression to represent the total amount of money he spent. Then find the total cost if one drink costs $3.

Answers

The total cost, if one drink costs $3 is $27.75

Let the cost of a pizza be x

Let the cost of a drink be y

If kiyo bought a pizza for 12.75 and four medium drinks to Pauli’s pizza, this expressed as x + 4y

Since a pizza costs $12.75, hence x = $12.75

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f(y) = 12.75 + 5y

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f(3) = 12.75 + 5(3)

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f(3) = 27.75

Hene the total cost, if one drink costs $3 is $27.75

Learn more on function here: https://brainly.com/question/9418047

PLSSS HELP THIS IS HARD ANYONE

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Answer:

270 degrees counterclockwise rotation/ the last answer

Step-by-step explanation:

reflection over the y axis wouldn't work bc the shape would still be a horizontal rectangle

dilation would change the size of the shape

and translation wouldn't map it correctly bc it would still be turned the wrong way

Answer:

270 degrees counterclockwise rotation

Step-by-step explanation:

you can use the formulas, but if you don't know them you can always draw

270 degrees counterclockwise = 90 degrees clockwise

(x,y) -> (y,-x)

A'(1,-2) -> A(-2,-1)

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C'(3,-5) -> C(-5,-3)

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Solve for a, round your answer to the nearest hundredth:-3(a + 9) - 5(a - 5) = 8

Answers

Answer:

22

Step-by-step explanation:

3(a+9)-5(a-5)=8

3a+27-5a+25=8

3a-5a+27+25=8

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-2a=8-52

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Answer:

3[tex]\frac{1}{4}[/tex]

Step-by-step explanation:

Answer:

13/4

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998−918

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998−738

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268

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134

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Answers

Answer:

  (x, y) = (5, -4)

Step-by-step explanation:

The second equation gives you an expression for x that can be substituted into the first equation.

  (2y +13) -3y = 17 . . substitute for x in the first equation

  -y = 4 . . . . . . . . . . . subtract 13 and simplify

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The solution is (x, y) = (5, -4).

_____

Additional comment

When faced with a system of linear equations, the first step is to look at them and observe where the variable terms are, and any relationships between coefficients. Several options are generally open to you for solving the equations. Methods generally taught first are ...

substitutionelimination

Substitution is handy when one of the variables or variable terms can be written (easily) in terms of the other variable. Elimination is handy when some simple multiple of one of the equations can be added to the other equation to cancel one of the variable terms (eliminate it).

Other available methods include matrix methods, Cramer's rule, and graphing. Working knowledge of all of these methods will help you identify the one that will be easiest to use in any given situation.

The availability of calculators able to use these methods greatly simplifies the task of finding a solution. It is simply a matter of entering the equations in the appropriate form.

One of my favorites is the graphing calculator, which only requires you type in the given equations and click on the solution point to find its coordinates.

15 points in 4 quarters

Answers

Is this u asking a question or just saying 15 points in 4 quarters?

Isn’t is 8 pints in 4 quarters because there’s 2 pints in each quarter.

Help Me Please!
A repairman charges an inspection fee plus $20 per hour. A customer
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Answers

Answer:

$108.50 for the 30% off an 1 hour and 35 min without the coupon 155 x 0.3 = 46.5. 155-46.5=108.50


The final price of a pair of socks is $6.40. It is on sale for 20% off. What is
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Answers

Answer: original price= $8

Step-by-step explanation:

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Discount = 8 × 20/100

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You save = $1.60

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Answer:

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Step-by-step explanation:

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If the mean of 16‚20‚25 and p is 20.Find the value of p.​

Answers

p=19
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Answers

Answer:

yes it is correct

Step-by-step explanation:

How do you write an equation of a line so that it is parallel or perpendicular to a given point??

Answers

The equation of a line so that it is perpendicular to a given point will be

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The equation of a line so that it is perpendicular to a given point will be

y-y0=m (x - xo)

The standard equation of the line is better written in point-slope form expressed as:

y-y0=m(x - xo)

where: m is the slope of the given line (x0, y0) is any point of the giuven line.

m is the slope of the given line

(x0, y0) is any point on the given line

If the given slope of the  line is m, the slope of the line perpendicular will be expressed as -1/m

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Answer:

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Step-by-step explanation:

A rectangular prism has 6 faces, 8 vertices (or corners) and 12 edges.

Answer:

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Step-by-step explanation:

You have to multiply 7 by 19. Which equation uses the Distributive Property to take this problem apan
A. 7(10 + 9) = 70 + 16
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Answers

C) 7(10 + 9) = 70 + 63
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Step-by-step explanation:

The one point where the lines intersect is one solution. If both points are on the same line it is one solution. If the lines do not intersect it is no solution.


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Answer:

I'm not sure but I think it's everything outside of circular, graphic and reflective. I'm only unsure with the last one but since it's 4 point I would assume it's 4 answers.

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Answers

Answer:

1= 41

2=85

3= 95

4=85

5= 36

6= 49

7= 188

Step-by-step explanation:

I think that's the answer

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B) m∠2 = 47
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Answers

The answer is C) m∠1 + m∠2 = 90

Explanation: So ∠1 is x and ∠2 is x-4

Basically you know than ∠3 is 90° ... And a straight line is 180° ..                            So technically we can just find out 180-90 is 90(the other angle 1 + 2).

To get 90° we'll add ∠1 and ∠2 in other ways, like technical thinking-

So you already know adding ∠1 and ∠2 is 90°. So ∠1 + ∠2 = 90°

In other words you can say m∠1 + m∠2 = 90

please solve quickly

Answers

Step-by-step explanation:

first you need to find the height

V = L×W×H

the volume your given is 880mm³

length is 22mm

width is 8mm

height is unknown

furthermore

V=L×W×H

880mm³= 22mm×8mm×H

880mm³= 176mm²×H

880mm³/176mm²=176mm²/176mm²×H

5mm=H

H=5mm

Surface Area= S.A

therefore S.A=2(L×W+ W×H +L×H)

=2(22mm×8mm+8mm×5mm+22mm×5mm)

=2(176mm²+40mm²+ 110mm²)

=352mm²+80mm²+220mm²

=652mm²

Question locate in image show working

Answers

If you divide that the answer would be 0.064

Find the area of the square

Answers

Answer:

144

Step-by-step explanation:

225-81 because with pythagorean thorem both sides should equal the C value or the bigger square.

how to turn x+7y=20 into y=mx+b

Answers

Answer:

  y = -1/7x +20/7

Step-by-step explanation:

Solve for y.

  7y = -x +20 . . . . . subtract x from both sides to get the y-term by itself

  y = -1/7x +20/7 . . . . divide both sides by the coefficient of x

In this form, you can see ...

m = -1/7b = 20/7 = 2 6/7

Answer:

y=-1/7x+20/7

Step-by-step explanation:

So they are asking us to put x+7y=20 into slop-intercept form (y=mx+b).

They're pretty much just asking us to solve for y.

x+7y=20

7x=20-x (Subtract x from both sides)

y=20-x/7 (Divide 7 on both sides to isolate y)

y=20/7-1/7x

y=-1/7x+20/7

So..

m=-1/7

b=20/7

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That would probably be zero for the answer, because if a number or an equation subtracts the same number or equation it will cancel itself out. Thus giving us zero.

Hope this help :D.

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Answer:

y=-2x-4

Step-by-step explanation:

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Answers

Answer:

5.40 x [tex]10^{2}[/tex]

Step-by-step explanation:

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