4.34 Systematic random samples. The last stage of the Current Population Survey (Example 7) uses a systematic random sample. An example will illustrate the idea of a systematic sample. Suppose that we must choose four rooms out of the 100 rooms in a dormitory. Because 1004 = 25, we can think of the list of 100 rooms as four lists of 25 rooms each. Choose one of the first 25 rooms at random, using Table A. The sample will contain this room and the rooms 25, 50, and 75 places down the list from it. If 13 is chosen, for example, then the systematic random sample consists of the rooms numbered 13, 38, 63, and 88. Use Table A to choose a systematic random sample of five rooms from a list of 200. Enter the table at line 120.