Chapter 4.5, Problem 140E

Acclaim or Attack. In the article “A Functional Analysis Comparison of Web-Only Advertisements and Traditional Television Advertisements from the 2004 and 2008 Presidential Campaigns” (Journalism & Mass Communication Quarterly, Vol. 90, No. 1, pp. 23–38), author C. Roberts explores whether a difference exists in purpose and content of web-only ads and television ads created by candidates in presidential campaigns. The following contingency table cross-classifies a sample of such advertisements by purpose and source. The purpose of the ad is classified as “acclaim” if the candidate acclaims himself/herself with positive statements about his/her credentials to be a better candidate. The purpose of the ad is classified as “attack” if the candidate attacks the opponent’s credentials or defends with refutations against the opponent’s attack.

1. a. Find P(S₂).
2. b. Find P(S₂ & P₁).
3. c. Obtain P(P₁ | S₂) directly from the table.
4. d. Obtain P(P₁ | S₂) by using the conditional probability rule and your answers from parts (a) and (b).