7.9. An Associated Press story (August 7, 2006) about a research study regarding the impact on teens of sexual lyrics in songs reported, "Teens who said they listened to lots of music with degrading sexual messages were almost twice as likely to start having intercourse ... within the following two years as were teens who listened to little or no sexually degrading music." The reported percentages were 51% and 29%.

(a) A 95% confidence interval for the difference between corresponding population proportions was (0.18, 0.26). Explain how to interpret it.

(b) The P-value is <0.001 for testing the null hypothesis that the corresponding population proportions are equal. Interpret.