Find margin of error for confidence interval for true mean

Reference no: EM13125611

We would like to estimate the true mean amount of money spent on textbooks by U of M students in one semester. Suppose that textbook costs are known to follow a normal distribution with standard deviation $111. We take a random sample of 23 students and calculate a mean cost of $365.

(a) Find the margin of error for a 89% confidence interval for the true mean cost of textbooks of U of M students in one semester.
(b) The 89% confidence interval for the true mean cost of textbooks for one semester is?

Reference no: EM13125611

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