Notice that x ma2 or x mb2 for each individual score

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: sing sA or sB, but we get a better estimate by using all of the data. The formula for sample variance from a single sample is the average of (X – M)2, and when we have two samples we do essentially the same thing. 2 MS = # A ( X " M A ) + #B ( X " M B ) df 2 (3) In this formula, the ∑A symbol means sum over all of Sample A, and ∑B means sum over all of Sample B. Notice that (X – MA)2 or (X – MB)2 for each individual score is an estimate of ! the population variance, σ2, and all Equation 3 does is average these estimates to get one single best estimate for σ2. The degrees of fre...
View Full Document

This document was uploaded on 02/25/2014 for the course PSYC 3101 at Colorado.

Ask a homework question - tutors are online