The standard deviation of a sample is estimated to be 100 and the standard error has been calculated to be 5. What size of sample will the researcher need to ensure a 95.5% confidence interval (Z=2.00)?
A) 400
B) 800
C) 1000
D) 10000

Question

Quizplus · Accepted Answer

The sample size (n) can be calculated using the formula for the standard error of the mean: Standard Error = Standard Deviation / sqrt(n). Rearranging this formula to solve for n gives n = (Standard Deviation / Standard Error)^2. Substituting the given values (Standard Deviation = 100, Standard Error = 5) yields n = (100 / 5)^2 = 400.

The Standard Deviation of a Sample Is Estimated to Be