Doctoral students often guess at sample size instead of calculating it properly. GPower is free software that tells you the minimum sample size you need based on your variables and target population. Use it before you run your experiment.
When you're doing an experimental design, you've got to have a sample size, and it's not just a guess. Yeah, I think I'll use 17. You do typically something known as a G*Power test where you put in a certain number of variables, and that then comes back and tells you, based on the population you're looking at, the minimum sample size that you're going to need to be able to do a study that has results that can be meaningful. Drop the word "help" in the comments below, and I'll send you the link to my free dissertation help community.
