Performs a two-way analysis of variance on the data in one column of a selected fully factorial Table and reports the fixed-effects anova table in the info window.

Settings

Column with data

the label of the column who's data will be analyzed.

First factor

the label of the column with the names of the levels for the first factor.

Second factor

the label of the column with the names of the levels for the second factor.

Table with means

if checked, a Table with the mean values of all the levels will be created.

Example

Suppose you want to check if fundamental frequency depends on the type of vowel and speaker type. We will use the Peterson & Barney vowel data set to illustrate this. The following script will first create the data set and then produce the two-way anova report.

This will produce the following anova table in the info window:

The analysis shows that F0 strongly depends on the vowel and also on the speaker type and, luckily, we do not have any interaction between the vowel and the speaker type. Besides the anova table there is also shown a table with the mean F0 values for each Vowel-Type combination which looks like:

The first column of this table shows the vowel codes while the first row shows the speaker types (child, man, woman). The last row and the last column of the table shows the averages for the factors Type and Vowel, respectively. The actual data are unbalanced because we have 300, 660 and 560 replications per column respectively (for each speaker we have two replcations of the data).

Algorithm

The formulas to handle unbalanced designs come from Khuri (1998).