From a population with a variance of 484, a sample of 256 items is selected. At 95% confidence, the margin of error is
A) 16.
B) 1.375.
C) 2.695.
D) 22.

Question

Quizplus · Accepted Answer

The formula for margin of error is:
Margin of Error = z * (σ/√n)
Where z is the z-score corresponding to the desired level of confidence, σ is the population standard deviation, and n is the sample size.
At 95% confidence, the z-score is 1.96.
Plugging in the values we get:
Margin of Error = 1.96 * (sqrt(484)/sqrt(256))
Margin of Error = 1.96 * (22/16)
Margin of Error = 2.695
Therefore, the margin of error is 2.695. Choice C is correct.

From a Population with a Variance of 484, a Sample