A population refers to a group of all items of interest to a statistics practitioner. The overall group of objects about which conclusions are to be drawn are called the population.

A subset or portion of the population that is actually obtained and that is used to draw conclusions about the population is called a sample.

Parameter refers to any statistical measure that is based on all units in the population.

Any statistical measure calculated on the basis of sample observation is called statistic.

If the data consist of different methods for estimating the sample and drawing the inferences about the features of the population, then it is termed as a statistical inference.