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