Within-Group versus Between-Group Variance in a Measured Trait
The load-bearing entry node for the whole sub-domain. Every downstream honesty skill — heritability misreading, the ecological fallacy, the group-difference fence — is a special case of splitting total variance into a part that separates the group means and a part that spreads people inside each group. Teach the split once, explicitly, as arithmetic on a measured trait; everything after it is an application.
Questions this Concept answers
- Why must the two components be kept separate when reading a comparison of groups?
Analysis of Variance (ANOVA) in Statistics
Analysis of variance (ANOVA) tests whether the means of three or more groups differ significantly by partitioning the total variance in observed scores into within-groups variance (variation among in…