INTRODUCTION TO STATISTICS

Statistics is a mathematical body of science that consists with the collection, analysis, interpretation or explanation and presentation of data.
Statistics: A branch of Mathematics that deals with the collection, organization, analysis and interpretation of data.

There are two type of statistics in Mathematics

Descriptive Statistics:

Statistics used only to describe the sample or summarize information about the sample.

Inferential Statistics

Statistics used to make inference or generalization about the broader population.

History of Statistics

Gottfried Achenwall (1719-1772) was a German philosopher, ARA historian, economist, jurist and statistician.

17th century – Probability theory 
18th century – Inferential statistics 
19th century – Statistics applied to educate and sociology
20th century – Regression and correlation

At present statistics use for many fields.

Accounting
sports
Environment
Marketing
Public health and etc.

Statistics Functions

Collection of data : The data could be carefully and scientifically collect to make final purpose
Classification : The collected data is grouped based on similarities and It helps to understand large and complex data.
Condensation : The data is summarized , precisely without loosing any information to do further statistical analysis.
Comparison : It helps to identify the best one and checking for the homogeneity of groups.
Correlation : It helps to find the relationship among variables.
Causation : To evaluate the impact of independent variable on the dependent variables.
Conclusion : Statistics helps to make correct decisions under uncertainty.

Statistics variables

The classification of variable can be summarized as follow.

Level Of Measurement In Statistics

Sampling Method

There two basic terms

Population : A population is the entire group that a complete set of
 Data , people with a specialized set of characteristics.

Sample: Sample is the specific group that choose from the population
 The size of sample is always less than the total size of the population.

Sampling Techniques

Sampling Techniques further………

Tutorial Created by G.G.K Janithri & D.A Godagedara