Doctoral researchers must be able to understand statistical tests and select the appropriate test for the research they are conducting. This assignment will allow you to practice your skills in selecting and using the appropriate statistical tests for a given research study.

General Information:

Use the following information to ensure successful completion of the assignment:

• Researchers wanted to explore self-esteem in adolescent boys and adolescent girls. Each respondent completed a 10-item self-esteem scale (they chose one rating for each item from a Likert-type scale, 1 = strongly disagree and 5 = strongly agree). The sum of the 10 ratings was each respondent’s self-esteem score. Their results were: t = 2.01, d = .90 (40 girls, 40 boys).
• This assignment uses a rubric. Please review the rubric prior to beginning the assignment to become familiar with the expectations for successful completion.
• Doctoral learners are required to use APA style for their writing assignments. The APA Style Guide is located in the Student Success Center.
• This assignment requires that at least two additional scholarly research sources related to this topic, and at least one in-text citation from each source be included.

Directions:

In an essay (250-500 words), use the scenario presented above to thoroughly answer the following questions:

1. What statistical test did the researchers use to determine if there was a statistically significant difference in levels of self-esteem between the boys and the girls?
2. What was the purpose of calculating a Cohen’s d? When is a Cohen’s d calculated? Interpret d=.90. What does it mean in this example?
3. What if the researcher compared the adolescent boys before treatment and again after treating them for depression? What type of t-test would be most appropriate in this case, and why?