A survey is planned to determine the mean annual family medical expenses of employees of a large company. The management of the company wishes to be 90​% confident that the sample mean is correct to within ±​$40 of the population mean annual family medical expenses. A previous study indicates that the standard deviation is approximately ​$253. a. How large a sample is​ necessary? b. If management wants to be correct to within ±​$15​, how many employees need to be​ selected?

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.4: Distributions Of Data
Problem 19PFA
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A survey is planned to determine the mean annual family medical expenses of employees of a large company. The management of the company wishes to be
90​%
confident that the sample mean is correct to within
±​$40
of the population mean annual family medical expenses. A previous study indicates that the standard deviation is approximately
​$253.
a. How large a sample is​ necessary?
b. If management wants to be correct to within
±​$15​,
how many employees need to be​ selected?
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