CHAPTER 8

Use two decimals for all calculations and four decimals for p values

1. A study examines whether self-esteem affects depression in children. A sample of 50 children with low self-esteem is given a standardized test for depression. The average score for the group is M = 93.5. For the general population, scores on the depression test form a normal distribution with a mean of = 90 and a standard deviation of =25. A researcher wants to test whether children with low self-esteem show significantly more depression? Test with = .05. What are the IV and the DV?

State the research question

State the hypothesesuse the correct symbols

What is the critical value of z? Calculate the test statistic.

What decision can you make?

What does that decision mean?

What type of error could you be making, and what would it mean?

2. The psychology department is gradually changing its curriculum by increasing the number of online course offerings. To evaluate the results of this change, a random sample of n = 36 students who registered for Introductory Psychology is placed in the online version of the course. At the end of the semester, all students take the same final exam. The average score for the sample is M = 76. For the general population of students taking the traditional lecture class, the final exam scores form a normal distribution with a mean of = 70 and = 15. Test with = .01.

State the research question.

State the hypotheses.

What is the critical value of z?

Calculate the test statistic.

What decision can you make?

What does that decision mean?

What type of error could you be making? What would it mean?