The following are some of the methods of sampling. 

1. Simple random sampling. 

2. Systematic sampling. 

3. Stratified sampling. 

1. Simple random sampling: In this method the samples are drawn in such a way that every unit of the population has equal chance of being included the in the sample. Random samples can be obtained by i) Lottery method ii) Use of Random numbers. 

2. Stratified sampling: In this method the population is divided in to different groups of units called strata, which are homogeneous with respect to a specific character. From each stratum appropriate number of units are randomly selected. This method is called Stratified sampling. 

3. Systematic sampling: In this method a population is serially arranged either in alphabetical or numerical order. Then first unit is selected at random between first and kthunit, and then every kth unit is selected. The number of units selected form the sample size.

Here = (No of units in the population/No. of units in the sample)

ie., One number will be selected between 1 and k by lottery method . Let it be ‘a’.

Then the sample units are : a, a+k , a+2k,…, a+ (n – 1)k.

For example, if N = 100, n = 10, then k = (N/n) = (100/10) = 10

If a = 5 , then. the sample units will be 5, 15 , 25, ….. , 995.