題目
A population mean is being estimated based on a sample of size 49.
The sample mean is 95, and the sample standard deviation is 21.
a. Construct CI95.
這有算出來是
CI95=(88.97,101.03)
b. Assume that another sample has a standard deviation of 21 (or very
close to 21). what sample size is required to have a CI95 that does
not exceed seven points in width? (Hint: Estimate the critical value
needed based on the information from the solution of part a.)
b小題解不出來，不知如何算出sample size
再麻煩大大解答，謝謝
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