6.What is sample?

In research a sample is a selected group of people or items from a larger population for research. The sample should be representative of the population.

Why we select sample?

1.      We want to draw conclusions about populations.

2.      We did not select data from all population.

3.      Data collection is time consuming.

4.      We did not study whole population due to time constrains.

What is Sampling bias?

Sampling bias is to do favor in the selection of sample. Sampling bias occurs when researcher did not collect enough information through questionnaires. The researcher did not have enough time to conduct interviews. The study population is not accessible. The researcher did not want to give accurate results and wants to favor any one.

Types of Sampling 

The convenience sampling

The researcher selects population according to his convenience from a population

Purposeful sampling

The researcher selects population according to the study purpose.

Types of Purposeful sampling

The random sampling

The researcher selects population from the sample randomly.

 Types of Random Sampling

Simple random sampling

Researcher collects information about each and every member of sample. A table of random numbers is used, and a number is assigned to every member.

Systematic Random Sampling

Researcher uses sampling frame to select the sample from population.

Stratified Sampling

researcher divides the population in groups and sub groups to select sample from population. Researcher decides the formula of selection of sample.

Cluster Sampling

researcher identifies the place and groups where the sample can be available and then selects the sample.