Asked Oct 18, 2019
If you want to be 99​% confident of estimating the population mean to within a sampling error of ±25 and the standard deviation is assumed to be 125​,what sample size is​ required?
check_circleExpert Solution
Step 1

The provided information’s are:

Standard deviation (σ) = 125.

Sampling error (E) = ±25

Confidence level = 99%

Here, sample size is required to be calculated.

Step 2

The formula to calculate the sample size is:

Z, хо
п 3

Image Transcriptionclose

Z, хо п 3 E

Step 3

The z-value at 99% confidence level is 2.576.


Z xo
n =
2.576 x 125

Image Transcriptionclose

Z xo n = E 2.576 x 125 25 =165.894 166


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