Find an estimate of the sample size needed to obtain the specified margin of error for the 95% confidence interval of a
population mean.
-Margin of error $= 6.3$, sample standard deviation $= 18$
A) 33
B) 16
C) 6
D) 206

Question

Quizplus · Accepted Answer

To estimate the sample size for a given margin of error, use the formula $ n = \left( \frac{Z \cdot \sigma}{E} \right)^2 $, where $ Z $ is the Z-score for the confidence level (1.96 for 95%), $ \sigma $ is the sample standard deviation, and $ E $ is the margin of error. Plugging in the values: $ n = \left( \frac{1.96 \cdot 18}{6.3} \right)^2 \approx 33 $.

Find an Estimate of the Sample Size Needed to Obtain =6.3= 6.3=6.3

Find an Estimate of the Sample Size Needed to Obtain $= 6.3$