Quiz about AP Statistics Inference Review

Question 1

Hint: Create some numbers!

Accepted Answer

D

Answer

A

Answer

B

Answer

E

Question 2

Hint: Read each answer choice carefully

Accepted Answer

E

Answer

A

Answer

B

Answer

C

Question 3

Hint: remember that lovely formula chart

Accepted Answer

B

Answer

A

Answer

D

Answer

E

Question 4

Hint: did you divide first?

Accepted Answer

C

Answer

B

Answer

D

Answer

E

Question 5

Hint: think logically...

Accepted Answer

C

Answer

A

Answer

B

Answer

E

Question 6

Hint: use some of them formulas!

Accepted Answer

A

Answer

B

Answer

D

Answer

E

Question 7

Hint
Power =1-P(Type II)
Lower Type II = Higher Alpha

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Question 8

Question 8.

Accepted Answer

C

Answer

A

Answer

B

Answer

E

Question 9

Hint
Check out that formula chart...again!

Accepted Answer

A

Answer

B

Answer

C

Answer

D

Question 10

Hint: For regression, you are estimating two things...how does that affect the degrees of freedom?

Accepted Answer

E

Answer

A

Answer

B

Answer

D

Question 11

Which of the following is the z critical value for a 99% confidence level?

Accepted Answer

2.58

Answer

2.33

Answer

2.97

Answer

3.09

Answer

3.29

Question 12

Which of the following is a difference between a t interval and a z interval?

Accepted Answer

z intervals are used if you know the population standard deviation and t intervals are used when you do not know the population standard deviation

Answer

t intervals are used if you know the population standard deviation and z intervals are used when you do not know the population standard deviation

Answer

t intervals are used when the sample size is large and z intervals are used when the sample size is small

Answer

z intervals are used when the population is not normally distributed

Answer

t intervals can only be used when the sample size is large whereas z intervals can be used for both large and small samples

Question 13

What size is needed to achieve a margin of error of 3% with 95% confidence when the population proportion of successes is 0.36?

Accepted Answer

984

Answer

983

Answer

256

Answer

255

Answer

250

Question 14

Which of the following would increase the width of a confidence interval?

Accepted Answer

Decreasing the degrees of freedom

Answer

Increasing the sample size

Answer

Decreasing the confidence level

Answer

Decreasing the standard deviation

Answer

Increasing the point estimate

Question 15

Which of the following statements about the width of a confidence interval is true if the sample size is doubled?

Accepted Answer

The confidence interval is narrower

Answer

The confidence interval is wider

Answer

It will have no effect on the width of the confidence interval

Answer

The width of the confidence interval will double

Answer

The width of the confidence interval will be half as wide

Question 16

A community wants to see if there is enough support to hold a town children's festival. 42% of 150 residents said they would participate in the event. What is the approximate standard error of p-hat?

Accepted Answer

0.02

Answer

0.03

Answer

0.24

Answer

0.04

Answer

0.002

Question 17

A psychologist reports that the result of a hypothesis test was statistically significant at the 0.05 level. Which of the following is consistent with this statement?

Accepted Answer

The p-value calculated was smaller than the significance level of 0.05

Answer

The significance level calculated was larger than 0.05

Answer

The significance level calculated was smaller than 0.05

Answer

The p-value calculated was larger than the significance level of 0.05

Answer

There was not enough information to make a decision

Question 18

A graduate student at a private university wanted to study the amount of money that students at his university carried with them. A recent study reported that the average amount of money carried by college students is $31. He decides to collect data and carry out a test to see if there is evidence that the average is higher for students at his university. Which of the following describes a Type II error in this context?

Accepted Answer

This would lead to the incorrect idea that there was no reason to believe that students at his university carry, on average, more than $31

Answer

This would lead to the incorrect idea that students at his university, on average, spend more money each month than students at other universities

Answer

This would lead to the incorrect idea that students at his university carry, on average, more than $31

Answer

This would lead to the incorrect idea that students at his university carry, on average, less than $31

Answer

This would lead to the correct idea that students at other campuses carry, on average, less than $31

Question 19

Bicycles purchased from a discount store come unassembled. The assembly instructions that come with the bicycle claim that the average assembly time is 30 minutes. A consumer group has received complaints from people who say that the assembly tie was greater than the time claims. They decide to purchase 40 of these bikes and have asked 40 different people to assemble them. The consumer group believed that it was reasonable to regard these 40 people as representative of the population of people who might purchase this bike. For this sample, they found that the assembly imes had a mean of 34.2 minutes and a standard deviation of 8.6 minutes. Is there convincing evidence that the claimed average assembly time is too low? Test at the 0.05 significance level. Assume conditions for inference have been met.

Accepted Answer

Yes, t=3.09, df=39, P-value=0.002

Answer

No, z=0.49 P-value=0.312

Answer

Yes, t=3.05, df=39, P-value=0.004

Answer

No, t=0.49, df=39, P-value=0.313

Answer

Yes, t=3.05, df=40, P-value=0.002

Question 20

A local group claims that more than 60% of the teens driving after 10 p.m. are exceeding the speed limit. They plan to collect data in hopes that a hypothesis test will provide convincing evidence in support of their claim. Which of the following is true about the hypotheses the group should test?

Accepted Answer

The alternative hypothesis states that more than 60% of the teens are exceeding the speed limit.

Answer

The null hypothesis states that less than 60% of the teens are exceeding the speed limit.

Answer

The null hypothesis states that more than 60% of the teens are exceeding the speed limit.

Answer

The alternative hypothesis states that less than 60% of the teens are exceeding the speed limit.

Answer

The alternative hypothesis states that less than or equal to 60% of the teens are exceeding the speed limit.

Question 21

Which of the following is closest to the P-value associated with a two-tailed t test with 20 degrees of freedom if the value of the test statistic is 2.0?

Accepted Answer

0.05

Answer

0.001

Answer

0.01

Answer

0.03

Answer

0.10

Question 22

Insurance companies charge higher monthly premiums for male drivers than female drivers between the ages of 16 and 25. Their rationale is that male drivers have more traffic violations that females. A consumer group believes this rationale is no longer appropriate. To investigate, a random sample of male drivers and a random sample of female drivers in the target age groups were selected. Each person was asked how many traffic violations they have received. The resulting data was used to compute the given summary statistics. A 98% confidence interval for the difference in population mean number of traffic violations is (-1.3, 1.5). Based on this confidence interval, is there evidence that the population means are different?

Accepted Answer

No. Since the interval contains zero, it is plausible that the mean number of traffic violations is greater for males than females.

Answer

Yes. Since the interval contains zero there is strong evidence that the mean number of traffic violations is greater for males than females.

Answer

Yes. Since the interval does not contain zero, there is strong evidence that the mean number of traffic violations is greater for males than females.

Answer

No. Since the interval does not contain zero, there is insufficient evidence that the number of traffic violations is the same for males and females.

Answer

Yes. Since the interval is wider for positive numbers, there is evidence that the mean number of traffic violations is greater for males than females.

Question 23

Which of the following statements are not true?

1) When samples are paired, a two-sample t test is appropriate.

2) The degrees of freedom for a paired t test is n-1, where n is the sum of the two sample sizes.

3) A two-sample z-test is used to test hypotheses about p₁-p₂ with large independent samples

Accepted Answer

1 and 2

Answer

1 only

Answer

2 only

Answer

3 only

Answer

1 and 3

Question 24

A new classroom strategy uses interactive technology to review information for a test. A random sample of 40 classroom teachers has been asked to use the technology with one of their classes and not with another class. The average test score for each class is then recorded for each teacher. Which would be the appropriate test to run to see if the technology helped?

Accepted Answer

Paired t test for population means

Answer

One-sample z test for a population mean

Answer

One-sample z test for a population proportion

Answer

Two-sample t test for population means

Answer

Two-sample z test for population means

Question 25

A soup manufacturer is deciding which company to use for their mushroom purchases. A random sample of 20 mushrooms for each company found 30% of the mushrooms from one company were damaged and 35% from the other company were damaged. What assumptions for the two proportions z test would be a concern? (select all that apply)

Accepted Answer

The sample size is not large enough

Answer

We don't know that they are random samples from both companies

Answer

The samples may not be independent

Question 26

A school district wishes to estimate the difference in the proportion of girls who purchase a school lunch and the proportion of boys who purchase a school lunch. Assuming that the conditions for inference are met, which of the following confidence intervals would be appropriate?

Accepted Answer

A two proportion z interval

Answer

A one-sample t interval

Answer

A two-sample t interval

Answer

A paired t interval

Answer

A one proportion z interval

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