ICS Statistics part 1 chapter 1 Definitions (page 1)

 INTRODUCTION TO THE STATISTICS

History of the statistics:

                        Statistics is a very old word. It is from the English language. The word Statistics comes from three different languages,

                                                Latin Word                 Status

                                                Italian Word                Statista

                                                German Word             Statistik

All these words mean “The political state”. In early ages the word statistics means “The information useful to the state”.

Observation:

                        In Statistics observations are the recordings of information in numerical form. For example height of students, height of plants, weight of students etc

Data:

                        Collection of facts and figures is called data.

Population or Statistical Population:

                        Population is defined as “ The collection of all individuals which posses some common characteristics. For example height of students, Number of children, Number of fans, etc. The size of population is denoted by “ N ”.

Sample:

                        Any part of the population is called sample. On the basis of sample study we draw conclusions about the population. The size of sample is denoted by “ n ”.

Parameter:

                        Any quantity computed from the population is called parameter. Parameters are constants and usually unknown. For example populations mean µ, population variance σ²

 are the parameters.

Statistic:

                        Any quantity computed from the sample is called statistic. Statistic is variable because it varies from sample to sample. For example sample mean , sample variance S².

Branches of Statistics:

                        Statistics may be divided into to two branches:

1.                  Descriptive Statistics

2.            Inferential Statistics