What is an Analysis of Variance and why are they done.

Question

Analysis of Variance (ANOVA) are done when you have more than 2 groups you are comparing. There are different types. In a one factor ANOVA you have one independent variable and more than 2 levels and 1 dependent variable. In a 2 factor ANOVA there are 2 independent variables each have 2 or more levels and still one dependent variable. These analysis are routinely done with SPSS statistical software and tell you which variables are statistically significant.

Answer 1

Analysis of variance (ANOVA) compares the means or averages of two or more groups. It is detecting any changes between groups to find out if they are significantly different. It is a useful statistic, for example, if you compare males and females on an IQ score. The IQ score is a scale variable and gender is a nominal or group variable. Many students and researchers use an ANOVA to answer their hypothesis. The data must be normally distributed to use an ANOVA, meaning it is bell-shaped using a histogram.