Section 1.1 Sampling 9 USING TECHNOLOGY We use Example 1.5 to illustrate the technology steps. TI-84 PLUS Drawing a simple random sample Step 1. Enter any nonzero number on the HOME screen as the seed. Step 2. Press STO > Step 3. Press MATH, select PRB, then 1: rand, and then press ENTER. This enters the seed into the calculator memory. See Figure A, which uses the number 21 as the seed. Step 4. Press MATH, select PRB, then 5: randInt Then enter 1, N, n, where N is the population size and n is the desired sample size. In Example 1.5, we use N = 40 and n = 5 (Figure B). Step 5. Press ENTER. The five values in the random sample for Example 1.5 are 27, 39, 30, 35, 17 (Figure C). Figure A Figure B Figure C MINITAB Drawing a simple random sample Step 1. Click Calc, then Random Data, then Integer... Step 2. In the Generate rows of data field, enter twice the desired sample size. For example, if the desired sample size is 10, enter 20. The reason for this is that some sample items may be repeated, and these will need to be deleted. Step 3. In the Store in column(s) field, enter C1. Step 4. Enter 1 for the Minimum value and the population size N for the Maximum value. We use Maximum value = 40 for Example 1.5. Click OK. Step 5. Column C1 of the worksheet will contain a list of randomly selected numbers between 1 and N. If any number appears more than once in Column C1, delete the replicates so that the number appears only once. For Example 1.5, our random sample begins with 16, 14, 30, 28, 17, ... (Figure D). Figure D
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