Descriptive Vs Inferential Statistics

Descriptive Statistics
Collection, presentation and description of data by graphs, tables and numerical summaries such as averages, variances etc.

Inferential Statistics
Interpretation of data as well as drawing conclusions and making generalizations from the data for larger group of subjects.

Population
Entire group of individuals or subjects about which we want to gain information.

Sample
A subgroup of a population from which we obtain information in order to draw conclusions for the entire population.

Parameter
It is the numerical summary for the entire population. A parameter is unknown because the entire population cannot be studied. We use the information based on a sample to arrive at the value of population parameter. The process is inferential.

Statistic
It is the numerical summary obtained from real data or sample. We can actually observe statistics. The process is descriptive.


We can roughly understand the whole process as follows:

Sample → Descriptive Statistics(statistics) → Inferential Statistics(parameters) → Population

So we take a sample, we describe it using graphs and numerical summaries like averages, variances etc then we apply inferential statistics and make generalizations about the population.


PS: Any Improvements/Corrections/Comments are welcome.