How to Make a Simple Random Sample

1. How to Make a Simple Random Sample Use of a Random Digits Table

2. If we want to select a simple random sample of five students from a class of 22 students, we can use a table of random digits as a tool. First we must number each student, in a process also called labeling. The class list is the sampling frame.

3. The students are: As you can see, they are already numbered. The numbers 1 through 9 are single digits, however, so we renumber them 01 through 09 so that each label has the same number of digits.

4. The labels are on the right-hand side. Now we go to a random digits table, similar, but not identical, to the one in your text.

5. RANDOM DIGITS TABLE

6. This is just a portion of an entire random digits table. Ordinarily, the starting point is randomly selected. For this example we start at the left end of row 2. We read digits in groups of two since that is the number of digits in our labels. (If we had one digit labels we would read one digit at a time; for three digit labels, read three digits at a time, etc.) (Spaces between digits are there simply to make the chart easier to read.) Our selection is {21,09,08,20,18}.

7. Comparing our selection {21,09,08,20,18} and our student list (sampling frame) we determine our SRS. Our SRS is Shae Wilson, Tommy McDowell, Jenna Kanoy, Dania Warren, and Adam Tesh.

8. The End