The very first step of statistical analysis is to find out the data is a population or sample. So, what the hell is population and sample and how they are different from each other…?

Let’s understand it by an example

Suppose you want to survey the salary of the people living in the particular state.

And if you survey all the people in that state it means you have surveyed the population(N).

But what you think is it possible to do it in real life…? Wouldn’t it be really tough…?

Therefore, we do survey of a small number of the people living in that state. Which means you have done a survey of a sample(n). This sample is a representation of the complete population. Your sample should always be a good representation of the population.

Population and Sample pictorial representation.

And if we calculate the average of salary of all the people in the state i.e. population it is called as Population Mean(μ). And if we calculate the average salary of small number of people i.e. sample it is called as Sample Mean(X̄).

Formula for Population Mean and Sample Mean

Population mean is not equal to the Sample mean but Sample Mean can tend to population mean if we go on increasing the sample size.

The END#