Question

HOW TO COMPARE 3 AREAS FROM A SAMPLE TO ANOTHER 3 AREAS FROM ANOTHER SAMPLE

Answer 1

In the modules on hypothesis testing we presented techniques for testing the equality of means in more than two independent samples using analysis of variance (ANOVA). An underlying assumption for appropriate use of ANOVA was that the continuous outcome was approximately normally distributed or that the samples were sufficiently large (usually nj> 30, where j=1, 2, ..., k and k denotes the number of independent comparison groups). An additional assumption for appropriate use of ANOVA is equality of variances in the k comparison groups. ANOVA is generally robust when the sample sizes are small but equal. When the outcome is not normally distributed and the samples are small, a nonparametric test is appropriate.