## Simple Random Sample (SRS)

**Overview:**

In a single random sample (SRS) a sample is randomly chosen from a population. Each combination of samples has an equal chance of being selected. This is the simplest and most common way of selecting a sample from a population or group.

**Sampling Frame**

A sampling frame is a list from which the sample is drawn from. For example if we are drawing a sample from a college. We could have a sampling frame of all full time students and randomly choose our sample from that.

**Sampling Variability**

When drawing randomly samples tend to differ from each other. Each time we draw it selects different outcomes. Differences like these lead to a difference in what variables we measure. Sampling variability is also called sampling error.

**Final Reminder:**

A SRS is the most basic of the sampling methods but it is easy to be confused when asked to describe how you would choose your sample using this method. Do not get mixed up with other methods, a SRS is where each thing in the population has an equal chance of being chosen.

Example:

A company is researching the effect their new product has on a general population and whether they are male or female affects it. They choose a random sample so 490 females and 510 males that walk past them on the street. Is this a SRS?

Answer: No it is not because not everybody in the population has an equal chance of being chosen.