From a population with a variance of 900, a sample of 225 items is selected.At 95% confidence, the margin of error is
A) 15.
B) 2.0.
C) 3.92.
D) 4.

Question

Quizplus · Accepted Answer

The formula for margin of error is

Margin of Error = Z * (standard deviation / sqrt(sample size))

Where Z is the Z-score for the desired confidence level. 
For a 95% confidence level, the Z-score is 1.96. 
Thus, Margin of Error = 1.96 * (sqrt(900) / sqrt(225)) = 3.92 (rounded to two decimal places). 
Therefore, the correct answer is C) 3.92.

From a Population with a Variance of 900, a Sample