Q2. Use the estimation method and compare models to test a hypothesis.(10 points)

You are part of a trivia team and have tracked your team's performance since you started playing, so you know that your scores are normally distributed with ? = 75 and ? = 12. Recently, a new person joined the team, and you think the scores have gotten better. Your goal is to answer the question: Are the new scores on average significantly better than 78? Follow the instructions below to determine the answer.

A. Calculate the sample mean of the following 9 weeks' worth of score data: 80, 78, 60, 78, 89, 84, 60, 91, 70.

B. Compute a 95% confidence interval for

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