## Sunday, 10 November 2013

### Two-way ANOVA test Calculator

Please fill in the number of first and second factor levels below at first. There must be between 2 and 10 levels for each of the two factors. Then click on the link below the text entry fields, which will create all the necessary textboxes. Each textbox is preceded by the label "Group a,b", where a and b are the level indices for the first factor and second factor respectively. There will be $n_1 \times n_2$ boxes, where $n_1$ is the number of first factor levels and $n_2$ is the number of second factor levels.

Number of first factor levels:

Number of second factor levels:

Simply click on the link near the top to add text boxes. Each text box stores a single group/dataset and needs to be filled in with comma separated numbers. Alternatively, you can choose two file entry methods:-

1. Select multiple single column CSV files to populate the text boxes by repeatedly pressing the Choose File button - there must be one distinct (and differently named) file for each text box i.e. one file per group. Each file must have the same number of samples (also known as replicates).
2. Select a single multi-column CSV file by pressing the Choose File button once, where the number of columns equals the total number of groups (each column contains the samples within a particular group)- all groups need to have the same number of samples. The number of columns must be equal to the number of first factor levels multiplied by the number of second factor levels.

As an example of loading a single multi-column CSV file, consider the dataset in http://www-stat.stanford.edu/~susan/courses/s141/exanova.pdf (where the number of first factor (detergent type) levels is 2 (Super and Best), and the number of second factor (temperature) levels is 3 (Cold, Warm and Hot)). The contents of the file will be as follows:-
# Data
4,7,10,6,13,12
5,9,12,6,15,13
6,8,11,4,12,10
5,12,9,4,12,13

There is a graph at the bottom which will display means for all the groups, once the calculate button is pressed.

The following post in this blog could be useful in helping how to interpret the three p-values calculated in a two-way ANOVA test.

Results pending...

 Line plot of the group means Group Means Second factor level number