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

Find the mean of the following 8, 12, 16, 10, 18, 15, 22, 16, 14, 17 ​

Answers

[tex]mean = \frac{sum \: of \: all \: observations}{number \: of \: observations} \\ = > mean = \frac{8 + 12 + 16 + 10 + 18 + 15 + 22 + 16 + 14 + 17}{10} \\ = > mean = \frac{148}{10} \\ = > mean = 14.8[/tex]

This is the answer.

For the transition matrix P = [0.8 2 0.2 2, 0.3 0.7]​, solve the equation SP = S to find the stationary matrix S and the limiting matrix Upper P overbar.

Answers

Answer:

Stationary matrix S = [ 0.6   0.4 ]

limiting matrix  P = [tex]\left[\begin{array}{ccc}0.6&0.4\\0.6&0.4\\\end{array}\right][/tex]

Step-by-step explanation:

Transition matrix

[tex]p = \left[\begin{array}{ccc}0.8&0.2\\0.3&0.7\\\end{array}\right][/tex]

solving the equation SP = S ( using Markova chain with 2 states )

stationary matrix,  S = [ a , 1 - a ]

given that  SP  = S

[ a , 1 - a ] * [tex]\left[\begin{array}{ccc}0.8&0.2\\0.3&0.7\\\end{array}\right][/tex] =  [ a , 1 - a ]

= a*(0.8) + ( 1 - a ) ( 0.3 ) = a

∴ a = 0.6

hence;  stationary matrix S = [ 0.6   0.4 ]

             limiting matrix  P = [tex]\left[\begin{array}{ccc}0.6&0.4\\0.6&0.4\\\end{array}\right][/tex]

a shipping boox has the dimentsions what is the volume of the box in cubic yards

Answers

Answer: 1/32

Step-by-step explanation:

Please help me solve this guys today is my last day & I’ve been trying so hard

Answers

y = x^2 - 3x - 4

Factored Form: y = (x - 4)(x + 1)

X-Intercepts: (4,0) and (-1,0)

Axis of Symmetry: x = 1.5

Vertex: (1.5, -6.25)

Domain: All real numbers

Range: y > -6.25

Hope this helps!

simultaneous equation

Answers

Answer:

(55/38,-16/19)

Step-by-step explanation:

4x -5y = 10

2x + 7y = -3

4x -5y = 10

-4x -14y = 6

-19y = 16

y = -16/19

2x  -112/19 = -57/19

x = 55/38

Find the missing side of the triangle

Answers

Answer:

missing side is 193

= 13.892443989449

Find the value of the trigonometric ratio, Make sure to simplify the fraction if needed

Answers

Answer:

Cos Z = 7/25

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

cos theta = adj / hyp

cos Z = 14/50

Cos Z = 7/25

▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

As the [tex]\triangle\sf{XYZ}[/tex] is a right angle traingle.

we know that,

[tex]\boxed{\underline{\sf{cos\blue{\theta}=\dfrac{adjacent}{hypertension} }}}[/tex] 

According to the question,

[tex]cosZ=\dfrac{adjacent}{hypertension}\\\\cosZ=\dfrac{14}{50}\\\\\pmb{\green{\sf{cosZ}=\frak{\dfrac{7}{25}}}}[/tex] 

▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

The base of a triangular prism has an area of 35 m2. This triangular prism has a height of 7 m. What is the volume of this triangular prism? ​

Answers

Answer:

The volume is 245 m^2

Step-by-step explanation:

the volume formula is aways base time height, or V = bh

so plot the number in, 35 x 7 = 245

help mePsychologists striving to understand the human mind may study the nervous system. Learning how the cells and organs (like the brain) function, help us understand the biological basis behind human psychology. The nervous system is composed of two basic cell types: glial cells (also known as glia) and neurons. Glial cells, which outnumber neurons ten to one, are traditionally thought to play a supportive role to neurons, both physically and metabolically. Glial cells provide scaffolding on which the nervous system is built, help neurons line up closely with each other to allow neuronal communication, provide insulation to neurons, transport nutrients and waste products, and mediate immune responses. Neurons, on the other hand, serve as interconnected information processors that are essential for all of the tasks of the nervous system. This section briefly describes the structure and function of neurons.​

Answers

Answer:

Hope this helps!

Step-by-step explanation:

Which statement best evaluates the effectiveness of the conclusion

paragraph?

Thesis Statement: My future job must include human interaction, a

nontraditional workspace, and teamwork.

Main Points:

1. Work with people

2. Work in a nontraditional workspace

3. Work in a place where coworkers share ideas

Conclusion: In the end, my future job will be one that allows me to

collaborate with my coworkers in dynamic and nontraditional

workspaces. If I am forced to sit behind a desk I will be extremely bored. Furthermore, I will be less productive if I am forced to work alone without the chance to discuss ideas with my coworkers. So the next time an adult asks me what I want to do when

I grow up, I will tell them a job without a desk, in an office full of

people. That's my dream job!

A. The conclusion is effective because it presents interesting information not addressed in the body paragraphs.

B. The conclusion is ineffective because it does not restate the thesis in a new way.

C. The conclusion is effective because it restates the thesis, summarizes the main points, and includes a satisfying close.

D. The conclusion is ineffective because it fails to leave the reader with a thought-provoking question.Which statement best evaluates the effectiveness of the conclusion  paragraph?

Thesis Statement: My future job must include human interaction, a

nontraditional workspace, and teamwork.

Main Points:

1. Work with people

2. Work in a nontraditional workspace

Answer:

Were is the question?

Step-by-step explanation:

Instructions: Find the missing side. Round your answer to the nearest tenth.

Answers

Answer:

x = 24.9

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

cos theta = adj / hyp

cos 43 = x /34

34 cos 43 = x

x=24.86602

To the nearest tenth

x = 24.9

02:Posttest 2: Fractions
6.
Order the numbers from least to greatest.
63
11
3
3
80 5 20
35

Answers

3,3,5,11,20,35,63,80

solve for θ:

sin(θ-70)=cos(θ)

pls help and explain step by step
thank you ​

Answers

Answer:

Use this rule : cosx = sin (90 - x)

sin( x -70) = sin (90 - x)

x-70 = 90 - x

2x = 160

x = 80

8 thousands÷10= ?
khan academny questions are confusing when you're doing math in the middle of the night

Answers

Step-by-step explanation:

Answer of your question is 800

find the measure of the indicated angle to the nearest degree​

Answers

Answer:

[tex]20^{\circ}[/tex]

Step-by-step explanation:

In any right triangle, the cosine of an angle is equal to its adjacent side divided by the hypotenuse.

Let the angle we want to find be [tex]\theta[/tex]. [tex]\theta[/tex]'s adjacent side is 49 and the hypotenuse of the triangle is 52.

Therefore, we have the equation:

[tex]\cos \theta=\frac{49}{52}[/tex]

Take the inverse cosine of both sides:

[tex]\arccos (\cos \theta)=\arccos(\frac{49}{52})[/tex]

Simplify using [tex]\arccos (\cos \theta)=\theta \text{ for }\theta \in (0, 180^{\circ})[/tex]:

[tex]\theta=\arccos(\frac{49}{52}),\\\theta=19.557214,\\\theta\approx \boxed{20^{\circ}}[/tex]


question
Instructions: Determine whether the following polygons are similar. If yes, type in
the similarity statement and scale factor. If no, type 'None' in the blanks.
L
35
M
х
w 18
50°
631
63
10
10
50°
35 N
o
Z
18
Y
Similar:

Answers

Answer:

No, the polygons aren't similar since they don't have a constant scale factor.

Solve the following inequality: |2x|<14 A. 7

Answers

Answer:

x<7

Step-by-step explanation:

it just is

Answer:

x > 7

 x < -7

Step-by-step explanation:

Absolute value inequalitiy entered

     |2x| > 14

Clear the absolute-value bars by splitting the equation into its two cases, one for the Positive case and the other for the Negative case.

The Absolute Value term is |2x|

For the Negative case we'll use -(2x)  

For the Positive case we'll use (2x)

-(2x) > 14  

    Multiply

     -2x > 14  

    Divide both sides by 2

     -x > 7  

    Multiply both sides by (-1)

    Remember to flip the inequality sign

     x < -7  

    Which is the solution for the Negative Case

(2x) > 14  

    Divide both sides by 2

     x > 7  

    Which is the solution for the Positive Case

x < -7

 x > 7

(-∞,-7)

 

   (7,+∞)

If f(x) = x/2 -2 and g(x) = 2x+ +x= 3, find (f + g)(x).

Answers

Answer:

.

.

.❥︎ᴀᴀɴᴋʜ ᴜᴛʜɪ ᴍᴏʜᴀʙʙᴀᴛ ɴᴇ ᴀɴɢᴅᴀɪ ʟɪ ,

.ᴅɪʟ ᴋᴀ sᴀᴜᴅᴀ ʜᴜᴀ ᴄʜᴀɴᴅɴɪ ʀᴀᴀᴛ ᴍᴇ ❣︎

.

.

0.9 x 100=
13.79 x 100=
29.894 x 100=

Answers

Answer:

multiplying by 100 "shifts" decimal point to the right by 2

90  

1379  

2989.4

Step-by-step explanation:

Answer:

0.9 x 100=90

13.79 x 100=1379

29.894 x 100=2989.4

Step-by-step explanation:

PLEASE HELP ASAP!!! i dont understand :(

Answers

Answer:

hello,

Step-by-step explanation:

y=k(x-a')²+b'

focus is (a',1/(4k)+b')

2x²=-120y

==> y=-2/120x²

==> y=-1/60(x-0)²+0

focus= (0,-15)

For the function f(x)=x+9/7-4x find f^-1(x)

Answers

Answer:

Step-by-step explanation:

[tex]f(x)=\frac{x+9}{7-4x} \\put ~f(x)=y\\flip~x~and~y\\f(y)=x\\y=f^{-1}(x)\\y=\frac{x+9}{7-4x} \\flip~x~and~y\\x=\frac{y+9}{7-4y} \\x(7-4y)=y+9\\7x-4xy=y+9\\-4xy-y=9-7x\\or\\4xy+y=7x-9\\y(4x+1)=7x-9\\y=\frac{7x-9}{4x+1} \\or~f^{-1}(x)=\frac{7x-9}{4x+1}[/tex]

HELP ILL GIVE BRAINLIEST

Answers

Answer:

the image/text is not there

Step-by-step explanation:

The 12th term of the arithmetic sequence is 10.5. The 18th term of this sequence is 13.5. Find the common difference and the first term.

Answers

Answer:

Common difference = 0.5

First term = 6.

Step-by-step explanation:

the 12th term a12 = a1 + d(12-1)   where a1 = first term and d = the common difference.

So a1 + 11d = 10.5 ....(A)    Similarly:

a1 + 17d = 13.5....(B)

Subtracting equations:

(B) - (A) :-

6d = 13.5 - 10.5 = 3

d = 3/6 = 0.5

From equation (A):

a1 + 11(0.5) = 10.5

a1 = 10.5 -5.5 = 5.

What is the nth term for number sequence
2;5;7;12;19

Answers

Answer:

13

Step-by-step explanation:

Have a nice day

HELP say im getting it wrong

the perimeter of the polygons is ?​

Answers

So the answer would be16*4=64

5 (6 - x) - 3 = 5 + 4 (x + 3)​

Answers

Answer:

X=0

Step-by-step explanation:

5(6-X)-3=5+4(X+3)

30-5x=5+4x+12

30-5-12=4x+5x

13=9x

13/9=x

Answer:

Use BODMAS rule

1st:B- solve bracket

2nd-O- open bracket

3rd;D:divide

4th:M- multiply

5th:A- Addition

6th :Subtract

Solution given;

5 (6 - x) - 3 = 5 + 4 (x + 3)

open bracket

30-5x-3=5+4x+12

30-3-5-12=5x+4x

10=9x

x=10/9

x=10/9

A cell phone tower services a circular region
within 20 miles of the tower. What is the
area of the region? (Use it = 3.14)

Answers

Area of a circle: pi x r^2

---r is the radius of the circle

A = pi x 20^2

A = 3.14 x 400

A = 1256 square miles

Hope this helps!

The t distribution should be used whenever _____. Group of answer choices the sample size is less than 30 the population is not normally distributed the sample standard deviation is used to estimate the population standard deviation None of the answers is correct.

Answers

Answer:

A: the sample size is less than 30

Step-by-step explanation:

Usually, the t-distribution is used instead of normal distribution in calculation of the mean of a normally distributed population when the sample size is small (n < 30) and if the population standard deviation is not known.

Thus, looking at the options, the correct one is Option A.

Please help: 6m - m = 5/6(6m - 10)

Will mark brainliest!!

Answers

Answer:

No solution.

Step-by-step explanation:

[tex]6m-m=\frac{5}{6}(6m-10)\\5m=5m-\frac{25}{3}\\0\neq -\frac{25}{3}[/tex]

Therefore, there is no solution.

Solve Q²= a(p²-b²)/p in form of y=mx+c

Answers

Answer:

We want to rewrite:

q^2 = a*(p^2 - b^2)/p

as a linear equation, in the form:

y = m*x + c

So we start with:

q^2 = a*(p^2 - b^2)/p

we can expand the left side to get:

q^2 = (a/p)*p^2 - (a/p)*b^2

q^2 = a*p - (a/p)*b^2

Now we can ust define:

a*p = c

Then we can replace that to get:

q^2 = -(a/p)*b^2 + c

now we can replace:

q^2 = y

b^2 = x

Replacing these, we get:

y = -(a/p)*x + c

finally, we can replace:

-(a/p) = m

then we got the equation:

y = m*x + c

where:

y = q^2

x = b^2

c = a*p

m = -(a/p)

In a sequence, the first term is 6 and the common difference is 4. The thirtieth (30th) term of
this sequence is
1) 118
2) 122
3) 1261
4) 130

Answers

If the first term is 6, there are 29 terms left until the 30th term so you do 29 x 4 = 116 then do 6 + 116 = 122
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