Tukey's 1 degree of freedom test of nonadditivity

This macro performs Tukey's 1 degree of freedom test of nonadditivity, which is a test for an interaction in a two-factor experiment with a single replicate.

Download the Macro

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Required Inputs

Three columns containing the results from a two-factor experiment with a single replicate

Optional Inputs

Use to change the default significance level (0.05) of the test.

Running the Macro

Suppose you have the following results of such a two-factor experiment in C1-C3 of the worksheet:

C1 C2 C3
Temp Pressure Y
40 20 7.9
40 25 11.3
40 30 13.5
50 20 12.7
50 25 10.9
50 30 10.2
60 20 11.3
60 25 10.8
60 30 11.0

To run the macro, choose Edit > Command Line Editor and type:

%TUK1DF C3 C1 C2

Click Submit Commands.

The sum of squares for both nonadditivity and error, the significance level, the test statistic, the critical value, and the conclusion will be provided in the session window.

Additional Information

"The test partitions the residual sum of squares into a single-degree-of-freedom component due to nonadditivity (interaction) and a component for error..."

Douglas C. Montgomery, Design and Analysis of Experiments, 5th Ed, 2001, pp 191-194.

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