Question 1

Your value of a statistic such as the t-test is greater than the critical value for α = .05 but less than the critical value for α = .01; consequently, you ______ the null hypothesis and state the level of significance as ______.

Accepted Answer

A) reject; p > .05 B) do not reject; p > .01 C) reject; p < .01 D) reject; p < .05

Question 2

According to the textbook, what is the difference between the terms "nonsignificant" and "insignificant"?

Accepted Answer

A)  "Insignificant" is not a statistical concept. 
B)  You use the term "insignificant" when you make the decision to reject the null hypothesis. 
C)  "Insignificant" implies p < .05; "nonsignificant" implies p < .01. 
D)  There is no difference between the two concepts-they mean the same thing.

Question 3

In which of the following situations would you MOST likely use the t-test for dependent means?

Accepted Answer

A)  comparing smokers versus non smokers 
B)  comparing stress levels before and after a yoga class 
C)  comparing first graders versus college students 
D)  comparing a sample mean versus a hypothesized population mean

Question 4

The mean of the sampling distribution of the difference is equal to one.

Accepted Answer

A) True 
 B)False

Question 5

Imagine the value of a statistic is greater than the critical value for α = .05 but less than the critical value for α = .01. Which is the MOST appropriate way to report the level of significance?

Accepted Answer

A)  p  .01 
C)  p  .05

Question 6

If your value of a statistic like the t-test falls in the ______ area of this distribution, you will ______ the null hypothesis because the probability of the statistic is ______.

Accepted Answer

A)  shaded; reject; high 
B)  shaded; not reject; high 
C)  unshaded; reject; low 
D)  unshaded; not reject; high

Question 7

Imagine the value of a statistic is greater than the critical value for α = .05 but less than the critical value for α = .01. In this situation you would ______ and state the level of significance as ______.

Accepted Answer

A)  reject the null hypothesis; p > .05 
B)  not reject the null hypothesis; p > .05 
C)  reject the null hypothesis; p > .01 
D)  reject the null hypothesis; p < .05

Question 8

In which of the following situations would you be most likely to use a one-tailed rather than two-tailed alternative hypothesis?

Accepted Answer

A)  The hypothesized effect can only be in one direction. 
B)  You want to set α at .10 rather than .05. 
C)  Your sample is very small. 
D)  You don't expect or want to reject the null hypothesis.

Question 9

A researcher comparing the means of two groups calculates the t-test for independent means and reports the following result: t(28) = 2.11, p <.05. This research study consisted of a TOTAL of ______ participants.

Accepted Answer

A)  14 
B)  15 
C)  28 
D)  30

Question 10

The assumption of normality is primarily concerned with ______.

Accepted Answer

A)  the difference between two sample means 
B)  the shape of the distribution of the dependent variable 
C)  how samples are drawn from populations 
D)  the difference between a sample mean and a population mean

Question 11

In the t-test for dependent means, the symbol sD stands for the ______.

Accepted Answer

A)  standard error of the mean 
B)  standard error of the difference 
C)  standard deviation of the mean 
D)  standard deviation of difference scores

Question 12

A researcher asks 20 people to take a sip of two different colas (first Coke and then Pepsi) and rate the flavor of both. In analyzing this data, how should the null hypothesis be stated?

Accepted Answer

A)  H0: µD ≠ 0 
B)  H0: µD = 20 
C)  H0: Coke = Pepsi 
D)  H0: µD = 0

Exam 9: Testing the Difference Between Two Means

Your value of a statistic such as the t-test is greater than the critical value for α = .05 but less than the critical value for α = .01; consequently, you the null hypothesis and state the level of significance as .