The word “Statistics” which comes from the Latin word status, meaning a political state. Originally, statistics meant information useful to the state such as information about the sizes of populations and armed forces.
The word statistics refers to “numerical facts systematically arranged” in the first place. That’s why the word statistics is always used in plural. Statistics as a subject which can be further divided into descriptive statistics and inferential statistics.
W Descriptive Statistics
Descriptive statistics is a branch of statistics which deals with concepts and methods concerned with summarization and description of important aspects of numerical data. This area of study deals with data aggregation, visualization and computation of numerical quantities that provide information about center tendency and spread of data.
Inferential Statistics
Inferential statistics deals with procedures for making inferences about the characteristics of a population. The knowledge about the population is derived from only a part of the data, known a sample. This area of statistics includes the estimation of population parameters and testing of statistical hypotheses. Inferential statistics relies on probability theory, as the inferences derived on the basis of a sample evidence cannot be absolutely certain.
Use Cases of Descriptive and Inferential Statistics
Descriptive Statistics
- A football player wants to find his goals average from the last 20 games.
- College student wants to describe the variation in his four test scores in Physics.
- A girl wants to determine the average weekly amount she spent on groceries in the past 6 months.
Inferential Statistics:
- A football player wants to estimate his chance of goal based on his current season average.
- Based on the first four leagues, student would like to predict the variation in his final Physics test scores.
- Based on last six months grocery bills, she would like to predict the average amount she will spent on groceries for the upcoming year.