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When each eligible subject has the same probability of being selected for inclusion in your sample, it is called ‘simple random sampling.’

For example, suppose a school administrator over 4 schools wishes to find out students’ opinions about food served in the school cafeterias. (S)he has a complete list of all students in the schools and decides to randomly select 150 students from the list.

In this example, each student throughout the 4 schools has an equal probability of selection to be given the survey; therefore, it is a simple random sample.

As the name implies, selecting a simple random sample is, well… simple!

- Assign each member of your population a numerical label.
- Use statistical software or a random digit table to select numerical labels at random.

A small catering business serves 9 reception centers. The owner wants to interview a sample of 4 clients in detail to find ways to improve services to his/her clients. To avoid bias, the owner chooses a simple random sample of size 4.

Step 1:

Each reception center is assigned a numerical label 1-9.

1- Darlene’s Wedding Center

2- Magic Moments Reception Hall

3- Rustic Realm Weddings

4- Romance Gardens

5- Classic Weddings

6- Old Time Chapel

7- Lovers Lane Weddings

8- Accents-Modern Weddings

9- Century Falls Reception CenterStep 2:

The owner decides to use a statistical software program to generate 4 numerical labels between 1 and 9 at random. The software returns the following numbers:

5, 8, 6, 4Therefore, the simple random sample to be interviewed in detail will be:

- Classic Weddings (5)
- Accents-Modern Weddings (8)
- Old Time Chapel (6)
- Romance Gardens (4)

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rev. 05-Aug-2019

Contact a NEDARC statistician for help with simple random sampling.