Question 1 2.5 out of 2.5 points
A study found statistically significant results for a hypothesis tested with an independent-samples t test.
The author of the study reported her effect size for the test as 0.82. According to Cohen's convention,
this effect size is considered:
Selected Answer: large.
Question 2 2.5 out of 2.5 points
A clinical researcher was interested in determining whether his interventions were effective in
minimizing depression symptoms among his participants. To assess the effectiveness of his treatment
program, he administered a depression inventory prior to his treatment and after his treatment. He
hypothesized that depression scores would be lower at time two compared to time one. He then
compared the mean differences between the two groups and found that his treatment was effective.
The dependent variable in this study is:
Selected Answer: depression scores.
Question 3 0 out of 2.5 points
The critical cutoff(s) for a two-tailed, paired-samples t test with 23 participants at a p level of 0.05 is
(are):
Selected Answer: –1.717 or 1.717.
Question 4 0 out of 2.5 points
A researcher studies 45 volunteer citizens from a small community and asks them about the amount of
caffeine (in milligrams) they ingest before and after lunch each day. The null hypothesis for this paired-
samples study could be:
Selected Answer: there is a difference between the amount of caffeine ingested before and after
lunch.
Question 5 2.5 out of 2.5 points
When scientists call a hypothesis test conservative, they mean that it is:
Selected Answer: difficult to reject the null hypothesis (i.e., the status quo).
, Question 6 2.5 out of 2.5 points
A researcher conducts a single-sample t test and finds statistical significance at the 0.01 level. The effect
size is then calculated and found to be 0.04. What might you conclude about the findings?
Selected Answer: While the results of the test are statistically significant, the effect size indicates that
they may not be practically significant. It might be the case that a very large sample was studied, driving
up the test statistic value.
Question 7 2.5 out of 2.5 points
In a within-groups design where one group is measured twice over time, the appropriate hypothesis test
is a(n):
Selected Answer: paired-samples t test.
Question 8 0 out of 2.5 points
The comparison distribution for an independent-samples t test is a distribution of:
Selected Answer: mean difference scores.
Question 9 2.5 out of 2.5 points
According to the null hypothesis, the mean difference for the comparison distribution in a paired-
samples t test is:
Selected Answer: always 0.
Question 10 2.5 out of 2.5 points
A study found statistically significant results for a hypothesis tested with an independent-samples t test.
The author of the study reported her effect size for the test as 1.24. What is true of the two sample
means?
Selected Answer: The two sample means are 1.24 standard deviations apart.
Question 11 2.5 out of 2.5 points
We have learned three t tests, including all of the following except:
Selected Answer: experimental-samples
Question 12 2.5 out of 2.5 points
Following are the results of an independent-samples t-test: t(18) = –2.11, p < 0.05. The results are:
Selected Answer: statistically significant.
A study found statistically significant results for a hypothesis tested with an independent-samples t test.
The author of the study reported her effect size for the test as 0.82. According to Cohen's convention,
this effect size is considered:
Selected Answer: large.
Question 2 2.5 out of 2.5 points
A clinical researcher was interested in determining whether his interventions were effective in
minimizing depression symptoms among his participants. To assess the effectiveness of his treatment
program, he administered a depression inventory prior to his treatment and after his treatment. He
hypothesized that depression scores would be lower at time two compared to time one. He then
compared the mean differences between the two groups and found that his treatment was effective.
The dependent variable in this study is:
Selected Answer: depression scores.
Question 3 0 out of 2.5 points
The critical cutoff(s) for a two-tailed, paired-samples t test with 23 participants at a p level of 0.05 is
(are):
Selected Answer: –1.717 or 1.717.
Question 4 0 out of 2.5 points
A researcher studies 45 volunteer citizens from a small community and asks them about the amount of
caffeine (in milligrams) they ingest before and after lunch each day. The null hypothesis for this paired-
samples study could be:
Selected Answer: there is a difference between the amount of caffeine ingested before and after
lunch.
Question 5 2.5 out of 2.5 points
When scientists call a hypothesis test conservative, they mean that it is:
Selected Answer: difficult to reject the null hypothesis (i.e., the status quo).
, Question 6 2.5 out of 2.5 points
A researcher conducts a single-sample t test and finds statistical significance at the 0.01 level. The effect
size is then calculated and found to be 0.04. What might you conclude about the findings?
Selected Answer: While the results of the test are statistically significant, the effect size indicates that
they may not be practically significant. It might be the case that a very large sample was studied, driving
up the test statistic value.
Question 7 2.5 out of 2.5 points
In a within-groups design where one group is measured twice over time, the appropriate hypothesis test
is a(n):
Selected Answer: paired-samples t test.
Question 8 0 out of 2.5 points
The comparison distribution for an independent-samples t test is a distribution of:
Selected Answer: mean difference scores.
Question 9 2.5 out of 2.5 points
According to the null hypothesis, the mean difference for the comparison distribution in a paired-
samples t test is:
Selected Answer: always 0.
Question 10 2.5 out of 2.5 points
A study found statistically significant results for a hypothesis tested with an independent-samples t test.
The author of the study reported her effect size for the test as 1.24. What is true of the two sample
means?
Selected Answer: The two sample means are 1.24 standard deviations apart.
Question 11 2.5 out of 2.5 points
We have learned three t tests, including all of the following except:
Selected Answer: experimental-samples
Question 12 2.5 out of 2.5 points
Following are the results of an independent-samples t-test: t(18) = –2.11, p < 0.05. The results are:
Selected Answer: statistically significant.
