Distinguish between random sampling and non-random sampling.

Hint: We can guess what is random sampling and non-random sampling simply by understanding the words that have been used.

Complete step by step answer:
A random sampling is the random selection of a sample and non-random sampling is the non-random sampling or selection of a sample. We can also use the word ‘biasing’ for this. The unbiased selection of a set from a relatively large set is known as random sampling and the biased selection of a set from a relatively large set is known as non-random sampling. In random sampling the probability of selection of any individual is equally probable while in non-random sampling it is not so. By equally probable we mean by chance and not by biasness.
There is one more difference between random sampling and non-random sampling. In non-random sampling an individual can have zero probability of being selected while in random sampling there can never be zero probability for selection of any individual.
Random sampling requires numbering of each element or individual while in non-random sampling selection of every nth element takes place.
It is said that Random sampling is the simplest method of data collection and generalising things about a particular group while Non-Random sampling is rather complicated.

Note: The method of sampling is used for census and other studies about population. The methods may yield particularly different results depending on the population.