Randomization on Minitab

The following is easier than the steps in Section 3.2:

1. Start as in Step 1 on p. 34: Enter r1 1's. r2 2's, etc. into a column. You can do this by hand. If your design is balanced, you can use Set Patterned Data (Calc menu). For example, if you have three groups of 4 each, specify to start at 1, end at 3, with increment 1, and then enter 4 in "Repeat each value".

2.  To randomize, choose Random Data from the Calc menu, then Sample from Columns. Enter the total number of observations desired (n = sum of the ri's) in "Number of  rows samples." Enter the column you just created  in the box "From columns" (Note that columns are labeled c1, c2, etc.unless you have given them a label. You can see the columns with entries by clicking in te box. You can then select and click in the box to enter a particular column.). Enter the column where you want the randomized numbers in "Store samples in." Example output (using 2,2, and 3 as treatment sizes):

obs treat randtr
1 1 1
2 1 3
3 2 1
4 2 3
5 3 3
6 3 2
7 3 2

(I have added a column "obs" for convenience.) This says assign experimental units 1 and 3 (first column) to treatment 1 (last column), units 6 and 7 to treatment 2, and units 2, 4, and 5 to treatment 3. (Note that the second column was just an intermediate step.)