The study mentioned in the previous exercise estimated in 1993 that 19.2% had engaged in unplanned sexual activities because of drinking alcohol; this was 21.3%

at the latest survey.

(a) Specify assumptions, notation, and hypotheses for a two-sided test comparing the corresponding population proportions.

(b) The test statistic z = 3.5 and the P-value = 0.0005.

Interpret the P-value.

(c) Some might argue that the result in

(b) reflects statistical significance but not practical significance. Explain the basis of this argument, and explain why you learn more from the 95% confidence interval, which is (0.009, 0.033).