7.16. In a survey conducted by Wright State University, senior high school students were asked if they had ever used marijuana. Table 7.12 shows software output. Treating these observations as a random sample from the population of interest:

(a) State a research question that could be addressed with this output.

(b) Interpret the reported confidence interval.

(c) Interpret the reported P-value.

TABLE 7.12 Sample yes N Sample prop 1. Female 445 1120 0.3973 2. Male 515 1156 0.4455 estimate for p(l) - p(2): -0.0482 95% CI for p(l) - p(2): ( -0.0887, -0.0077)

Test for difference = 0 (vs not = 0):

z = -2.33 P-value = 0.020