Question 1

Given that in a one-tailed test you cannot reject H0, can you reject H0 in a two-tailed test at the same α?

Accepted Answer

A)  Yes.
B)  No.
C)  Maybe. B

Question 2

Power is the probability of rejecting the null hypothesis when it is false and is equal to 1 - β.

Accepted Answer

A) True 
 B)False  True

Question 3

A hypothesis test may be statistically significant, yet have little practical importance.

Accepted Answer

A) True 
 B)False  True

Question 4

If the null and alternative hypotheses are H0: μ ≤ 100 and H1: μ > 100, the test is right-tailed.

Accepted Answer

A) True 
 B)False

Question 5

For a right-tailed test of a hypothesis for a population mean with n = 14, the value of the test statistic was t = 1.863. The p-value is:

Accepted Answer

A)  between .05 and .025.
B)  between .10 and .05.
C)  greater than .10.
D)  less than .01.

Question 6

Regarding the probability of Type I error (α) and Type II error (β), which statement is true?

Accepted Answer

A)  β > α
B)  β 
C)  α + β = 1
D)  Power = 1 - β.

Question 7

A power curve for a mean is at its lowest point when the true μ is very near μ0.

Accepted Answer

A) True 
 B)False

Question 8

In hypothesis testing, we are trying to prove the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 9

In a two-tailed test, a statistician got a z test statistic of 1.47. What is the p-value?

Accepted Answer

A)  .0708
B)  .1416
C)  .0874
D)  .0301

Question 10

"Currently, only 20 percent of arrested drug pushers are convicted," cried candidate Courageous Calvin in a campaign speech. "Elect me and you'll see a big increase in convictions." A year after his election a random sample of 144 case files of arrested drug pushers showed 36 convictions. For a right-tailed test, the p-value is approximately:

Accepted Answer

A)  0.9332
B)  0.0668
C)  0.0435
D)  0.0250

Question 11

The critical value of a hypothesis test is based on the researcher's selected level of significance.

Accepted Answer

A) True 
 B)False

Question 12

For a right-tailed test of hypothesis for a population mean with known σ, the test statistic was z = 1.79. The p-value is:

Accepted Answer

A)  .0367
B)  .9633
C)  .1186
D)  .0179

Question 13

If sample size increases from 25 to 100 and the level of significance stays the same, then:

Accepted Answer

A)  the risk of Type II error would decrease.
B)  the risk of Type I error would decrease.
C)  the risk of both Type I and Type II errors would decrease.
D)  the risk of neither Type I nor Type II error would decrease.

Question 14

Increasing the level of significance shifts the power curve upward, ceteris paribus.

Accepted Answer

A) True 
 B)False

Question 15

The researcher's null hypotheses is H0: σ2 = 420. A sample of n = 18 items yields a sample variance of s2 = 512. The test statistic is:

Accepted Answer

A)  34.09
B)  20.72
C)  14.77
D)  must know α to answer.

Question 16

We can assume that the sample proportion is normally distributed if:

Accepted Answer

A)  we have 10 successes in the sample.
B)  we have 10 failures in the sample.
C)  we have both 10 successes and 10 failures in the sample.
D)  the population is known.

Question 17

The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it. A trial sample of 25 employees shows that 16 are dissatisfied. The p-value for a right-tailed test is:

Accepted Answer

A)  .1337
B)  .4192
C)  .0901
D)  .0808

Question 18

Which of the following is correct?

Accepted Answer

A)  When sample size increases, both α and β may decrease.
B)  Type II error can only occur when you reject H0.
C)  Type I error can only occur if you fail to reject H0.
D)  The level of significance is the probability of Type II error.

Question 19

In graphing power curves, there is a different power curve for each sample size n.

Accepted Answer

A) True 
 B)False

Question 20

In the hypothesis H0: π = π0, the value of π0 is derived from the sample.

Accepted Answer

A) True 
 B)False

Exam 9: One-Sample Hypothesis Tests

Given that in a one-tailed test you cannot reject H₀, can you reject H₀ in a two-tailed test at the same α?

Power is the probability of rejecting the null hypothesis when it is false and is equal to 1 - β.

A hypothesis test may be statistically significant, yet have little practical importance.

If the null and alternative hypotheses are H₀: μ ≤ 100 and H₁: μ > 100, the test is right-tailed.

For a right-tailed test of a hypothesis for a population mean with n = 14, the value of the test statistic was t = 1.863. The p-value is:

Regarding the probability of Type I error (α) and Type II error (β) , which statement is true?

A power curve for a mean is at its lowest point when the true μ is very near μ₀.

In hypothesis testing, we are trying to prove the null hypothesis.

In a two-tailed test, a statistician got a z test statistic of 1.47. What is the p-value?

The critical value of a hypothesis test is based on the researcher's selected level of significance.

For a right-tailed test of hypothesis for a population mean with known σ, the test statistic was z = 1.79. The p-value is:

If sample size increases from 25 to 100 and the level of significance stays the same, then:

Increasing the level of significance shifts the power curve upward, ceteris paribus.

The researcher's null hypotheses is H₀: σ² = 420. A sample of n = 18 items yields a sample variance of s² = 512. The test statistic is:

We can assume that the sample proportion is normally distributed if:

The Melodic Kortholt Company will change its current health plan if at least half the employees are dissatisfied with it. A trial sample of 25 employees shows that 16 are dissatisfied. The p-value for a right-tailed test is:

Which of the following is correct?

In graphing power curves, there is a different power curve for each sample size n.

In the hypothesis H₀: π = π₀, the value of π₀ is derived from the sample.