Factor Divide

This dialog can be used to divide a factor column within a spreadsheet into a two or more factors. An example of when dividing a factor may be useful is when generating factors for a design, such as a Latin square, to study several factors and their interactions. For a 12 by 12 Latin square you may have a single factor that you want to divide into factors A and B with 2 and 4 levels respectively. The factors A and B could be derived by dividing the 12 level treatment factor into two factors with levels (1,1,1,1,2,2,2,2,3,3,3,3) and (1,2,3,4,1,2,3,4,1,2,3,4) respectively.

The maximum number of factors that can be produced from the divide operation is six. If a factor is to be divided into more that six new factors then the dialog can be used again on the resulting factors from the previous split. For each factor that is created from the split the name and number of levels must be supplied, also the product of the number of levels of the resulting factors must be the same as the number of levels of factor being divided. The dialog calculates the divisors for the number of levels in the factor being divided and then these are used to initialize the fields for the number of levels of each factor. If the number of levels does not have enough divisors, then the dialog will not let you specify that number of resulting factors. For example if the number of levels is 12, then at most only 3 factors can be formed as 12 has prime divisors of 2, 2, and 3. If the number of levels of a factor are prime, then a warning will be provided, as this factor may not be divided. The resulting factor columns are added back to the spreadsheet from which the factor being divided came.

Combining factor levels, the opposite operation to factor division, can be performed using the factor combine dialog. This combines a number of factor columns into a single factor.

Factor to Divide

A drop down list of the factors in the spreadsheet. Select the factor to be divided into the resulting factors.

Number of Resulting Factors

Allows you to select the number of factors to divide the factor into (between 2 and 6). If the number of levels of the factor to be divided has at most n prime divisors, then this number must be less or equal to n. On changing this, divisors of n will be entered into the Num Levels input fields.

Resulting Factors

For the number of resulting factors, Factor 1-, a name and number of levels (Num Levels) must be supplied in the input fields. The number of levels can be increased or decreased using the arrows beside the edit box.

Action Buttons

OK	Select the columns of the spreadsheet and close the dialog.
Cancel	Close the dialog.

Example

This example shows the Factor Divide dialog being used to split a 12 level factor Treat into two 3 and 4 level factors, A and B. The resulting spreadsheet is show along side the dialog.

The next example shows the same factor Treat being divided into three 2, 2 and 3 level factors, A, B, and C. The resulting spreadsheet is show along side the dialog.

Factor to Divide

Number of Resulting Factors

Resulting Factors

Action Buttons

Example

See Also