How to calculate the sample size for a survey without margin of error?

Question

I'm doing a survey for my dissertation and I need to know how many people to interview. I want to calculate the sample size for this using Excel but I don't know how. Every source I read says I need to include the margin of error, but when I want to calculate the margin of error, they say I need the sample size.

I need to know how to figure out the sample size easily. I desperately need to know within two days.

Answer 1

You DECIDE what margin of error you want in your study and then calculate the necessary minimal sample size to achieve it. If you are doing a proportion, typical margins of error are 1% or 5%.

You should read an example problem in your textbook for calculating sample size. You will see they decide in advance what margin of error they want. The margin of error controls the width of the confidence interval i.e. the precision you want in your result.