EXAMPLE 3 How to choose an SRS using software
Joan’s small accounting firm serves 30 business clients. Joan wants to interview a sample of five clients to find ways to improve client satisfaction. To avoid bias, she chooses an SRS of size 5.
Step 1: Label. Give each client a numerical label between 1 and 30. Here is the list of clients, with labels attached, using 1 to 30:
1 | A-1 Plumbing | 16 | JL Appliances |
2 | Accent Printing | 17 | Johnson Commodities |
3 | Action Sport Shop | 18 | Keiser Construction |
4 | Anderson Construction | 19 | Liu’s Chinese Restaurant |
5 | Bailey Trucking | 20 | MagicTan |
6 | Balloons Inc. | 21 | Peerless Machine |
7 | Bennett Hardware | 22 | Photo Arts |
8 | Best’s Camera Shop | 23 | River City Antiques |
9 | Blue Print Specialties | 24 | Riverside Tavern |
10 | Central Tree Service | 25 | Rustic Boutique |
11 | Classic Flowers | 26 | Satellite Services |
12 | Computer Answers | 27 | Scotch Wash |
13 | Darlene’s Dolls | 28 | Sewer’s Center |
14 | Fleisch Realty | 29 | Tire Specialties |
15 | Hernandez Electronics | 30 | Von’s Video Games |
Step 2: Software. Use statistical software to generate a random integer between 1 and 30. Repeat this process, ignoring any values that were previously generated, until you obtain five different integers between 1 and 30. Joan used software and generated the numbers 18, 9, 10, 3, 9, and 1. The five different integers are 18, 9, 10, 3, and 1, so the sample is the clients Keiser Construction, Blue Print Specialties, Central Tree Service, Action Sport Shop, and A-1 Plumbing.