Systematic Sampling: Capturing the Essence of Comprehensive Researc

There are three main types of systematic sampling:

1. Systematic Random Sampling
2. Linear Systematic Sampling
3. Circular Systematic Sampling

The following is a breakdown of how each type is executed:

Systematic Random Sampling:

This is the most basic type of systematic sampling and these are the steps taken to conduct it:

• Calculate sampling interval using the formula i = N/n
• Pick a starting point “r”. This point must be between 1 and the number of the sampling interval (between 1 and i). For instance, in the example shown above, the sampling interval is 40 so we must pick a number between 1 and 40.
• Using the sampling interval, choose successive elements until the desired sample size is reached.

Linear Systematic Sampling:

This type of sampling employs a “skip method” whilst choosing the sample group. The skip or sampling interval is “k”, where k = N/n. These are the steps to select the sample group using linear systematic sampling:

• Create a sequential list of the target population/population units.
• Decide on a sample size “n”.
• Compute the “skip” (sampling interval) using the formula: k = N/n
• Choose a random number “r”, between 1 and k (sampling interval).
• Add “k” to “r” to select a second unit, and continue doing so to select as many units required in the sample size.

Circular Systematic Sampling:

In this method of sampling, a sample starts again from the point it ends. The following steps can be used to select elements using circular systematic sampling:

• Calculate the sampling interval using formula of “k”, k=N/n
• Choose a random start “r” between 1 and N
• Using the sampling interval “k”, skip through the circle to select units until “n” number of units are selected.
• This method allows for “N” number of samples being selected rather than just “k”.