One Way ANOVA

The one-way ANOVA procedure performs an analysis-of-variance to test whether or not the means of two or more samples are equal. In one-way ANOVA, there is only one treatment factor variable. It assumes all the samples are drawn from normally distributed populations with equal variance. One-way ANOVA is an extension of the two-sample t-test, which yields the same result when the factor variable has only two levels.

In addition to determining that differences exist among the means, the one-way ANOVA procedure provides multiple means comparisons in order to identify which particular means are different; it tests for equal variance among the samples; and it performs a power analysis, computing the actual power and the hypothetical power for the analysis.

The ANOVAOneWay Dialog Box

Examples

Algorithms

To perform a One-Way ANOVA:

1. Select Statistics: ANOVA: One-Way ANOVA. This opens the ANOVAOneWay dialog box.
2. Specify the Input Data Form, indexed or raw, and then fill Input Data, and the desired tests, such as Means Comparison, Tests for Equal Variance, and Power Analysis.
3. Upon clicking OK, an analysis report sheet is generated that lists the degrees of freedom, F statistic, the associated p-value, and the test conclusion.