ANOVA REML AND REGRESSION - When to use

#1
Dear All

I am trying to get my head around when to use ANOVA when to use regeression and when to use REML. As I understand REML can be used in situations where you would normally use ANOVA (2 variables?) but for unbalanced / correlated data, or where you would use linear regression but have more than one source of variation / correlation in the data. Can anyone expand? The smipler the explanation the better!

Jo