By Variables

Specify the variables that define separate groups of rows on which binning is to be performed. For example, choosing Chromosome as the BY variable indicates that binning of intensities is to be performed separately for each chromosome .

BY Variables

BY variables are optional (in most processes) variable specifications whose values define groups of observations , such as hour, month, or year. BY variables can enable analyses to be performed separately on different groups as defined by that variable. Choosing a BY variable such as gender ( ADSL variable = SEX ) groups the subjects by gender and conducts two separate analyses: one for males and one for females.

Alternatively, specifying a BY variable enables you to animate an image so that you can see how response values change according to some grouping, like over time.

To Specify One or More BY Variables:

Specify the input data set.

All of the variables in the input data set are displayed in the Available Variables field.

Examine the list of available variables.

Highlight one or more variables by which you want to group your results. To highlight multiple variables, hold down Ctrl while clicking.

Click to add the highlighted variable(s) to the By Variables field, as shown below:

Note : If no BY variables are specified, the analysis is conducted across all the subjects.