Psych 302

David J. Weiss

Solutions for Distribution Problem Set 1

1. z = 2.83, Probability = .0023 (Normal approximation to binomial; n = 300, p = .5)

2. t = 2.14, df = 35. Critical value of t at .05 level = 1.69, so data are consistent with tribal belief. Causality not clear, because other differences between Kwakiutls and other tribes may exist (random assignment is not possible)

3. z = 3.79. Probability of an overloaded elevator is .00007

4. t = 1.87, df = 48. Critical value of t at .05 level = 2.01, so no significant difference

5. z = 4.00, so those lucky Californians have significantly higher income because critical value of z at .05 level is 1.645