Systematic sampling is a statistical method involving the selection of elements from an ordered sampling frame. The most common form of systematic sampling is an equal-probability method.

Simple random sampling is the basic sampling technique where we select a group of subjects (a sample) for study from a larger group (a population). Each individual is chosen entirely by chance and each member of the population has an equal chance of being included in the sample. you can do this by selecting every k individual from a list of all population. 

Note that Simple random sampling may be easily done in Excel.

Hello Wasantha,

From your query, it sounds as if there is not an existing enumeration of the population. If this is true, then the advice Cristian Ramos-Vera has offered will be difficult to implement.

You may have to settle for a proxy enumeration of the population.

Here's a simple example:

Suppose you wanted to sample heads of households in a county, but there was no official enumeration of this population.

You could try proxies such as:

1. Residential accounts for electric power in that county (which the power company could potentially furnish, especially if the local government was the energy vendor).

2. Tax rolls for land-owners in the county.

3. Most recent census data for the county.

4. The post office may maintain a list of all known mailing addresses within a county.

5. Voter registration rolls for the county.

It's possible that a proxy like the ones mentioned would give a satisfactory representation of the target population. From there, you would proceed with Cristian's steps #2-5.

Good luck with your work.

You might see my post here: https://www.researchgate.net/post/What_would_be_a_minimum_representative_sample_size_for_a_population_of_70

I certainly agree with David Morse Best wishes, D. Booth