Test-retest reliability

Read the following case study. Use the information in the case study to answer the accompanying follow-up questions.

Case Study

Dr. Zak developed a test to measure depression. He sampled 100 university students to take his five item test. The group of students was comprised of 30 men and 70 women. In this group, four persons were African American, six persons were Hispanic, and one person was Asian. Zak’s Miraculous Test of Depression is printed below:

1.I feel depressed: Yes No

2.I have been sad for the last two weeks: Yes No

3.I have seen changes in my eating and sleeping: Yes No

4.I don’t feel that life is going to get better: Yes No

5.I feel happy most of the day: Yes No

Yes = 1; No = 0

The mean on this test is 3.5 with a standard deviation of .5.

Follow-Up Questions

1.Sally scores 1.5 on this test. How many standard deviations is Sally from the mean? (Show your calculations)

2.Billy scores 5. What is his standard score?

Prepare a 75 – to 80-word response for each of the remaining questions.

Can you think of other possible threats to test/retest reliability?

What are the advantages and disadvantages of test-retest reliability?

Sample Solution