Pub. date: 2008 | Online Pub. Date: November 27, 2007 | DOI: 10.4135/9781412953948 | Print ISBN: 9781412928168 | Online ISBN: 9781412953948| Publisher:SAGE Publications, Inc.About this encyclopedia
Analysis of Variance
Gudmund R. Iversen
Most analyses of relationships between variables involve the use of independent and dependent variables. Analysis of variance (ANOVA) is a collection of methods where the independent variable(s) are categorical (nominal) and the dependent variable is quantitative (metric, interval/ratio) with a numerical scale. The analysis compares the means of the dependent variable for the groups defined by the independent variable(s). A more appropriate name might be analysis of means, but variances are used to determine whether means are different. The simplest case has one independent variable with two categories and one dependent variable. For example, ANOVA can be used to analyze the relationship between the independent variable gender (categorical) and the dependent variable blood pressure (quantitative). The analysis compares the mean blood pressures for females and males. This comparison can also be made using a t test for the comparison of two means, and such a t test is a ANOVA ...