Question

What is the difference between a random sample and a simple random​ sample?

Answer 1

Random Sample: A random sample is a sample that is chosen randomly. Now, what is a sample? Sample is nothing but a small part of the whole population, sample should truly represent the population with all its characteristics. So analysis are being done on this sample and decisions are made regarding the population based on the inferences from the sample. For a sample to be a true representative of a population, there should be no bias while selecting sample points, in other words it should be truly random. These random samples are drawn based on different sampling method of which one is simple random sample.

Simple random sample is the sample obtained as a result of applying simple random sampling technique. Now what happens in these technique? Let's take an example, from a population of 100 if I wish to select sample consisting of 10 data points, i take a bowl and prepare chits numbered 1 to 100, put them in the bowl, mix all the chits thoroughly and pick up 10 chits from the bowl, the data points corresponding to these 10 chits form my sample. Here there is equal probability of any chit being picked, there is no bias involved (There is a possibility if the chits are not thoroughly mixed).