Meaning of ANALYSIS OF VARIANCE (ANOVA):
This is a statistical procedure used to test differences between the distribution around the means (see measures of central tendency) of some characteristic within and between various groups. For example, we might wish to know how social class affects life expectancy. We would collect information about age at death and social class, divide the sample into, say, five social classes, and then see how the degree of variation within any of the social classes compares with the difference between the five classes. If the variation within each class is markedly less than the variation between them, then we would conclude that social class is strongly associated with (and in this case therefore in all likelihood a major determinant of) life expectancy.