For the Pure Error DF, consider the multiple instances in the Big Class.jmp sample data table where more than one subject has the same value of height. In general, if there are g groups having multiple rows with identical values for each effect, the pooled DF, denoted DFp, is as follows:

For the Pure Error SS, in general, if there are g groups having multiple rows with the same x value, the pooled SS, denoted SSp, is written as follows:

Because Pure Error is invariant to the form of the model and is the minimum possible variance, Max RSq is calculated as follows: