EXAMPLE 3.13

Randomize the subjects. Let’s use random digits to perform the randomization that we performed using Excel in Example 3.12. Because the labels range from 1 to 10, we can use two digits for our labels

01, 02, 03, 04, 05, 06, 07, 08, 09, 10

when we select random digits from Table B. We could also have changed our labels to 0 through 9 and then we would only need to use single digits from Table B.

Start anywhere in Table B and read two-digit groups. Suppose we begin at line 175, which is

80011 09937  57195 33906  94831 10056  42211 65491

The first 10 two-digit groups in this line are

80  01 10  99  37  57 19  53  39  06

Each of these two-digit groups is a label. The labels 00 and 11 to 99 are not used in this example, so we ignore them. The first 10 labels between 01 and 10 that we encounter in the table choose subjects who will receive the treatment. Of the first 10 labels in line 175, we ignore seven because they are too high (over 10). The others are 01, 10, and 06. Continue across line 175 and 176 and verify that the next two subjects selected correspond to labels 03 and 04. Our randomization has selected subjects 1, 3, 4, 6, and 10 to receive the treatment. The remaining subjects, 2, 5, 7, 8, and 9 will receive the placebo control.