# Sample Standard Deviation Of The Sample Wins Essay

Sample Mean: 80.05

Sample Standard deviation: 11.9405

2. Assume that the population is normally distributed, but the population standard deviation is not known. [8 POINTS]

(a) Use your sample data to find a 95% confidence interval for the true mean number of wins for all Major League teams: -Next Page

(b) State the margin of error of the confidence interval: 5.5883

(c) How can you increase the precision of this confidence interval, without changing the sample size?

Use a lower confidence level: Decreasing the confidence level will decrease the width of the confidence interval. This will lead to a narrower and a more precise confidence interval.

3. Assume that the population standard deviation is 10 and assume the population is approximately normally distributed. Find the sample size that would be required to determine a 95% confidence interval if we want to be within 3 games of the true mean. That is, we want the margin of error, e, to not exceed 3 games. [4 POINTS]

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4. Using your sample data, conduct a hypothesis test at the alpha = 0.05 significance level. You may assume that the population standard deviation is not known and that the population is approximately normally distributed. [14 POINTS

Is there sufficient evidence to conclude that the mean number of wins for all teams is more than 75? (a)

(b) Using the critical value approach: State…