sample size help. - for ph.d.non.stats person wanting to learn!lol

#1
i want to run a bunch of anovas to compare means between two groups. There are approximately 135 items, composing 5 scales. I'm wondering how to calculate the size of the sample for each of the groups i would need to find differences at the 0.05 level? Does anyone know how or does anyone know the answer?
 

KimR

New Member
#2
power analysis

Before I start data collection I do a power analysis for small, medium and large effect sizes. You can figure out how many participants you need based on how many conditions and what size effect you are looking for. The procedure is in most graduate level stat books. Also, there is a free ware software program I have used (G power...you can goggle it. The authors are from a university on Germany), that will crunch the numbers for you. Best of luck.