Below is a table listing those contrasts with anĮxplanation of the contrasts that they make and an example of how the syntax works. Use, of which special (used in the above examples) is only one. SPSS has a number of built-in contrasts that you can This isīecause the two-way ANOVA has a smaller mean square residual than the one-way ANOVA. Note that the F-ratios in these contrasts are larger than the F-ratios in the one-way ANOVA example. Now let’s try the same contrasts on b but in a two-way ANOVA. Using the contrast command in a two-way ANOVA To obtain the t-value, you will have to divide the contrast estimate by the Each contrast must be separated by a comma. Note that you can enter multiple contrasts inĪ single subcommand, as shown below. This contrast is also statistically significant (F(1, 28) = 95.724, p = This contrast is also statistically significant (F(1, 28) = 110.634, p = Now, let’s devise some contrasts that we can test:Ģ) the average of groups 1 and 2 versus the average of groups 3 and 4ģ) the average of groups 1, 2, and 3 versus group 4 glm y by b It is quite clear that there is a significant overall F for the independent variable b Using the contrast command in a one-way ANOVA glm y by b.

The variable a is an independent variable with two levels, while b is an independent variable with four levels. The variable y is the dependent variable. These data are from a 2×4 factorial design but the same data can also be used for one-way ANOVA examples. Let’s use an example dataset, crf24.sav, adapted from Kirk (1968, First Edition).

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