Random digit table

To use one, give every individual a numeric label of the same length, pick a starting line, then read digits in groups of that length. Skip any group that falls outside your range of labels, skip any label you have already taken, and stop once you have the count you need. For example, to pick 3 of 40 students, label them 01 to 40 and read two digits at a time: 07, 63, 24, 07, 31 gives students 07, 24, and 31, because 63 is out of range and the second 07 repeats. The AP course describes random mechanisms such as a random number generator or drawing numbered slips of paper, and a table is the paper version of the same idea.