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.

Purpose Acclaim Attack P1 P2 Total Web-only ad 20 42 62 S1 Television ad 332 176 508 S2 Total 352 218 570

a. Find P(S2).

b. Find P(S2 & P1).

c. Obtain P(P1 | S2) directly from the table.

d. Obtain P(P1 | S2) by using the conditional probability rule and your answers from parts

(a) and (b).