An annual championship event is the most widely watched sporting event in a country each year. In recent​ years, there has been a great deal of interest in the ads that appear during the game. These...

An annual championship event is the most widely watched sporting event in a country each year. In recent​ years, there has been a great deal of interest in the ads that appear during the game. These ads vary in length with most lasting 30 seconds or 60 seconds. The accompanying data represent the ad length and ad scores from a recent championship. Complete parts​ (a) through​ (c).

a. Assuming that the population variances from the​ 30-second ads and the​ 60-second ads are​ equal, is there evidence of a difference in the mean score between the two types of​ ads? Use

Let

be the mean score for the​ 30-second ads and

be the mean score for the​ 60-second ads. Determine the hypotheses. Choose the correct answer below.