A store buys 12 sweaters for $96 and sells them for $264. How much profit does the store make per sweater?

a national survey conducted among a simple random sample of 1,507 adults shows that 56% of americans think the civil war is stil

soldier1979 [14.2K]

a)

$z=4.658\\p_v=P(z > 4.65)=1-P(z < 4.65)=1.581x*10^{-6}$

b) By assuming a significance level of α = 0.05 and observing that $p_v$ > α, we can reject the null hypothesis at this level of significance. And in this instance, it makes sense that more than 50% of Americans believe that the Civil War still has an impact on American politics and political life.

c) The confidence interval at 90% would be shown (0.527;0.593).

About 54% to 59% of all Americans, in our opinion, believe that the Civil War is still significant today.

<h3>What is a survey?</h3>

A survey is a set of questions used in human subject research with the goal of gathering specific information from a certain population. Surveys can be carried out via the phone, by mail, online, at street corners, and even in shopping centers.

a)

1) The presented data and the notation "n=1507" refer to the random sample of Americans, "X" denoting the proportion of those Americans in the sample who believe that the Civil War is still significant to American politics and political life, and "p cap" denoting the estimated number of those Americans.

Since the problem specifies that majority α=0.05 represents the significance threshold, $p_0$ is the number that we wish to test (no given, but is assumed)

Z would stand for the statistic (interesting variable), and $p_v$ for the p value (variable of interest)

P is the percentage of the public that believes that the Civil War still has an impact on American politics and political life.

2) Useful concepts and formulas

The allegation that more Americans than 50% believe the Civil War is still significant to American politics and political life needs to be tested through a hypothesis (Majority). :

Alternative Hypothesis: p $\geq$ 0.5

Null Hypothesis: p $\leq$ 0.5

The proportion is thought to have a normal distribution.

This test for the percentage of union membership has one tail higher.

Verify whether the sample conforms to the presumptions required for the test to be applied.

a) The random sample must be representative; in this situation, there is no mention of this issue, but it is safe to presume that it exists.

b) The sample size must be sufficient.

$np_0=1507*0.5=753.5 > 10\\n(1-p_0)=1507*(1-0.5)=753.5 > 10$

3. Determine the statistic.

The formula used to calculate the statistic is as follows:

$z=\frac{p-p_0}{\sqrt{\frac{p_0(1-p_0)}{n} } }= \frac{0.56-0.5}{\sqrt{\frac{0.5(1-0.5)}{1507} } }=4.658$

P value= $p_v=P(z > 4.65)=1-P(z < 4.65)=1.581*x*10^{-6}$

According to the alternative hypothesis, the following would be the p value:

P value= $p_v=P(z > 4.65)=1-P(z < 4.65)=1.581*x*10^{-6}$

Using this formula, the confidence interval would be determined.

p ± $z_{\frac{\alpha }{2}}\sqrt{\frac{p(1-p)}{n} }$

With the value of $\alpha$ and $\alpha _2$ , we can get the quantile necessary for the interval in the normal standard distribution for the 90% confidence interval.

$z_{\frac{\alpha }{2} }=2.58$

adding the following to the formula for the confidence interval:

$0.56-2.58\sqrt{\frac{0.56(1-0.56)}{1507} } = 0.527\\0.56+2.58\sqrt{\frac{0.56(1-0.56)}{1507} } = 0.593$

Also provided would be the 90% confidence interval (0.527;0.593).

About 54% to 59% of all Americans, in our opinion, believe that the Civil War is still significant today.

And because the interval does not contain the value of 0.5, we can conclude that, at a 90% level of confidence, the percentage of Americans who believe that the Civil War is still relevant to American politics and political life is higher than 0.5. This result is consistent with the result of part b.

To know more about survey, visit:

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6 0

2 years ago

Raymond has two seven foot long boards, and wants to cut fifteen inch long peices from each; what is the greatest number of peic

anastassius [24]

7ft = 84in 84 ÷ 15 = 5.6 pieces he can cut from each board. Since .6 is not a whole piece measuring 15 inches long, he can only cut 5 pieces from each board.

So, 5 x 2 = 10

He would be able to cut 10 pieces measuring 15 inches long.

Hope this helps :)

7 0

3 years ago

Read 2 more answers

A dog jumps straight up. Y=-16t^2+20t models the motion of the dog, where "t" is the time in seconds and "y" is the height of th

alina1380 [7]

Answer:

Step-by-step explanation:

The motion of the dolphin is quadratic

i.e y=-16t²+20t

To get the maximum height the dolphin will reach

We need to find the point of inflexion. i.e dy/dt=0

dy/dt=-32t+20

Then set dy/dt=0

0=-32t+20

Then, -32t=-20

t=0.625

Let find d²y/dt²

d²y/dt²=-32. Since this is negative then the point t=0.625 is the maximum point the dolphin can reach

Then substitute t=0.625 into y

y=-16t²+20t

y=-16(0.625)²+20(0.625)

y=6.25ft

Then the maximum height the dolphin can reach is 6.25ft

Using discriminant

Formular method

y=-16t²+20t

So the dog height y<7

y=-16t²+20t <7

-16t²+20t-7<0

a=-16, b= 20. c=-7

t=(-b±√b²-4ac)/2a

Using the a, b and c direct for the discriminant

D=b²-4ac

D=20²-4×-16×-7

D=-48

Which is a complex number

Then the dolphin can reach the height

Then we need to model the D to be greater than 0

Therefore,

D>0

b²-4ac>0

We cannot do anything to a and b it is already given

a=-16, b=20

(20)²-4(-16c)>0

400+64c>0

64c>-400

Then

c>-6.25

Divide both side by - and the inequality sign will change

Therefore -c<6.25

So the dog height y<6.25

y=-16t²+20t <6.25

Therefore the maximum height is 6.25.

If it is greater than that then, we are going to have a complex root movement which is not possible for the dolphin .

5 0

3 years ago

Darrin put the numbers 7.25, 7.52, and 5.72 and 5.27 in order from greatest to least.Is his work correct?Explain

aksik [14]

If the order of the numbers in the question are the order Darrin put theem in then no, his work is not correct. this is because 7.25 is not greater than 7.52. the real order should be 7.52,7.25, 5.72, 5.27

8 0

2 years ago

Read 2 more answers

Evaluate the expression. –5g – 6 for g = –2

Artist 52 [7]

Answer:

4

Step-by-step explanation:

Given that:

= –5g – 6

put g = -2

= -5(-2) - 6

= 10 - 6

= 4

i hope it will help you!

6 0

3 years ago

Read 2 more answers

A store buys 12 sweaters for $96 and sells them for $264. How much profit does the store make per sweater?​

A store buys 12 sweaters for $96 and sells them for $264. How much profit does the store make per sweater?