Question

If the population standard deviation is o=10, how large a sample is necessary to have a standard error that is less than 5 points?

Answer 1

Use the following questions & solve for n to find the sample size: sample error = o / sqrt(n). Next you would arrange equation to solve for sample size: sqrt(n) = o / sample error. Then square both sides to get: n = (o / sample error)^2.