Question

If the population standard deviation is σ= 5, how large a sample is necessary to have a standard error that is

a. less than 3 points?

b. less than 2 points?

c. less than 1 point?

Answer 1

a) For a standard deviation of 5, and standard error value of 3 points, the sample size is obtained here as:

Therefore 3 is the required sample size here.

b) For a standard error of 3, the sample size is obtained here as:

Therefore 7 is the required sample size here.

c) For a standard error of 1, the sample size here is obtained as:

Therefore 25 is the required sample size here.