Descriptive/Inferential Statistics Review

Due Monday, November 29 during class - correct responses will be posted on Monday night

Worth: 5% extra credit maximum

(1%if less than 50% correct; 3% if 50-75%; 5% if 76-100%)

Given the following data, calculate:

1. The mean for each group
2. The variance and standard deviation
3. A t-test (obtained)
4. Specify the null and alternative hypotheses
5. Specify whether you will be using a one- or two-tailed analysis
6. Calculate degrees of freedom
7. Choose a probability level
8. Identify the critical value of t (from the t table posted on Moodle).
9. Indicate whether or not the null should be accepted or rejected. Why or why not?
10. What do the results suggest?

Hypothesis - Mood is negatively related to performance; people in bad moods will perform at a higher level than those in good moods.

Independent Variable - Mood - Operationally defined by putting participants in a good or bad mood by having them view positive or negative pictures.

Dependent Variable - Performance- Score on a performance assessment (i.e., solving riddles; 50 points indicates maximum level of performance)

Positive Mood Negative Mood

20 30

21 35

24 37

25 39

28 40

29 45

30 47

33 48

34 48

39 50

As an added review, you should also determine mode and median.