Do social recommendations increase ad effectiveness? A study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. Data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. The results were:

a. Set up the null and alternative hypotheses to try to determine whether brand recall is higher following a social media recommendation than with only web browsing.
b. Conduct the hypothesis test defined in (a), using the 0.05 level of significance.
c. Does the result of your test in (b) make it appropriate to claim that brand recall is higher following a social media recommendation than by web browsing?