SOLUTION: PROBLEM 6 Playbill magazine reported that the mean annual household income of its readers is $119,155. (Playbill, January 2006). Assume this estimate of the mean annual

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Question 326468: PROBLEM 6



Playbill magazine reported that the mean annual household income of its readers is $119,155.
(Playbill, January 2006). Assume this estimate of the mean annual household income is based on
a sample of 80 households, and based on past studies, the population standard deviation is known
to be σ = $30,000.
a. Develop a 90% confidence interval estimate of the population mean.


b. Develop a 95% confidence interval estimate of the population mean.



c. Develop a 99% confidence interval estimate of the population mean.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!

a)Xave%2B-+%281.645%2Asigma%29%2Fsqrt%28N%29=119155%2B%281.645%2A30000%29%2Fsqrt%2880%29
.
.
b)Xave%2B-+%281.96%2Asigma%29%2Fsqrt%28N%29=119155%2B%281.96%2A30000%29%2Fsqrt%2880%29
.
.
c)Xave%2B-+%282.576%2Asigma%29%2Fsqrt%28N%29=119155%2B%282.576%2A30000%29%2Fsqrt%2880%29