Several studies (Keinan, 2002, for example) have found evidence that belief in magic and luck increased as stress levels increased. The more stressed people were, the more likely they were to engage in magical thinking. Suppose you did your own study examining the relationship between test anxiety and belief in the power of a lucky charm. You ask one group of students to bring their own personal lucky charm to their statistics final exam. Another group is the control group and has to take their statistics exam without any lucky objects present during the test.

Scores on statistics final exam with and without a lucky charm

Without Lucky Charm	With Lucky Charm
82	64
95	38
68	100
75	42
70	77
70	100
79	97
79	99
76	95
76	48

Use the data to answer the following questions:

1. Calculate the mean for each group.
2. Calculate the standard deviation for each group.
3. In your opinion, does having a lucky charm result in better performance on the exam? How do the two groups differ? How are they similar?