Statistics is the science of collecting, organizing, analyzing, and interpreting data to aid decision-making, divided into descriptive and inferential statistics. Descriptive statistics summarizes and presents numerical data, while inferential statistics makes inferences about a population based on sample data. Key concepts include population, sample, parameter, and observation.

1. Definition of statistics
Statistics is a science of collecting,
organizing, presenting, analyzing and
interpreting data to assist in making
more effective decisions.

2. Branches of statistics
1- Descriptive Statistics
2- Inferential Statistics

3. Descriptive Statistics
Descriptive statistics is that branch of statistics
which deals with concepts and methods
concerned with summarization and
description of the important aspects of
numerical data. This area of study consists of
condensation of data , their graphical displays
and the computations of a few numerical
quantities that provide information about the
centre of the data and indicates the spread of
the observations

4. Inferential Statistics
Inferential statistics deals with procedures for
making inferences about the characteristics
that describe the larger group of data or only
the part of the data. This area includes the
estimation of population parameters and
testing of statistical hypothesis.

5. Population
A population or a statistical population is a
collection or set of all possible observations
whether finite or infinite ,relevant to some
characteristics of interest.

6. Sample
A sample is a part or subset of population.
Parameter
A parameter is a numerical measurement
describing some characteristics of a population

7. Data
The Facts and Figures that are collected , Analyzed
and Interpreted.
Observation
Any thing that can be measured or observed
is called observation