Faux pas. Eight junior high school students were taken to a shopping mall. The number of socially inappropriate behaviors (faux pas) by each student was counted. The students were then enrolled in a program designed to promote social skills. After completing the programs, the subjects were again taken to the shopping mall and the number of social faux pas was again counted. Table 11.3 lists data from this experiment.

TABLE 11.3 Data for Exercise 11.23. Number of faux pas before and after an intervention.

OBS. VISIT1 VISIT2 1 5 4 2 13 11 3 17 12 4 3 3 5 20 14 6 18 14 7 8 10 8 15 9 Data are fictitious. Data file = FAUXPAS.SAV.

(a) Calculate the change in the number of faux pas within individuals (i.e., calculate DELTA for each observation).

(b) Calculate the means and standard deviations for visit 1, visit 2, and their differences (DELTAS).

(c) Create a stemplot of the differences (DELTAS). Interpret your plot.

(d) Would you use t-procedures on these data?

(e) Test the mean decline for statistical significance. Use a twosided test. Show all hypothesis-testing steps.