od and food. In a study of the effects of mood on evaluation of nutritious food, 208 subjects were ran- domly assigned to read either a happy story (to induce a positive mood) or a control (no story, neutral mood) group. Subjects were then asked to evaluate their atti- tude toward a certain indulgent food on a nine-point scale, with higher numbers indicating a more positive attitude toward the food. The following table summa- rizes data on the attitude rating: 14 Group n X S Positive mood 104 4.30 2.05 Neutral mood 104 5.50 1.74 (a) What are the standard errors of the sample means of the two groups? (b) What degrees of freedom does the conservative Op- tion 2 use for two-sample t procedures for these data? (c) Test the null hypothesis of no difference between the two group means against the two-sided alterna-