Question 1
5 out of 5 points
Twenty college students experience the effects of alcohol on reaction time. They
perform very basic timed responses in a driving simulator both before and after

consuming several alcoholic beverages. The researcher collects a reaction time
result for each of the 20 students before and after intoxication, for a total of 40
measures. What are the degrees of freedom for this study?

Question 2
5 out of 5 points
What is the paired-samples t test statistic for the following difference scores: –2, –
19, +17, –22, –6?

15.57
Question 3
5 out of 5 points
A clinical researcher was interested in determining whether her interventions were
effective in minimizing depression symptoms among participants. To assess the
effectiveness of the treatment program, she administered a depression inventory
prior to treatment and after treatment. She hypothesized that depression scores
would be lower at time 2 compared to time 1. She then compared the mean
differences between the two groups and found that the treatment was effective. The
independent variable in this study is:
Question 4

5 out of 5 points
Which of these is NOT an assumption of the paired-samples t test?
Selected Answer:
There are more than 30 sample data.
Answers:
The dependent variable is a scale variable.
Participants are randomly selected.
There are more than 30 sample data.

The population is normally distributed.
Question 5
5 out of 5 points
A clinical researcher was interested in determining whether her interventions were
effective in minimizing depression symptoms among participants. To assess the
effectiveness of the treatment program, she administered a depression inventory
prior to treatment and after treatment. She hypothesized that depression scores
would be lower at time 2 compared to time 1. She then compared the mean
differences between the two groups and found that the treatment was effective. The
dependent variable in this study is:

Question 6
5 out of 5 points
As the sample size becomes larger, the t distributions become:

Question 7
5 out of 5 points
What would be the decision for a two-tailed paired-samples t test where the t
statistic is –2.67, with cutoffs of ±2.776?

Question 8
5 out of 5 points
A researcher collects 15 data points that yield a mean of 9.164 and a standard
deviation (based on N – 1) of 2.377. If the researcher is comparing the sample to a
population mean of 10.6, what is the value of the test statistic?
Selected Answer:
–2.339
Answers:

0.611
–0.604
–1.943
–2.339
Question 9
5 out of 5 points