Question

Assume that you want to construct a 95% confidence interval estimate of a population mean. Find...

Assume that you want to construct a 95% confidence interval estimate of a population mean. Find an estimate of the sample size needed to obtain the specified margin of error for the 95% confidence interval. The sample standard deviation is give. E= 20.3 cm, sample standard deviation =321.0 cm.

1201
961
916
Cannot tell from the given information
Math   Statistics-And-Probability   
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Homework Answers

Answer #1

Solution :

Given that,

standard deviation = = 321.0 cm

margin of error = E = 20.3

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.960

Sample size = n = ((Z/2 * ) / E)2

= ((1.960 * 321.0) / 20.3)2

= 961

Sample size = 961

Answer 961 is correct.

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