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Statistics is concerned with the scientific method by which information is collected,
organised, analysed and interpreted for the purpose of description and decision making.
Examples using statistics are: Hang Seng Index, Life or car insurance rate, Unemployment
rate, Consumer Price Index, etc.
There are two subdivisions of statistical method.
(a) Descriptive Statistics - It deals with the presentation of numerical facts, or data, in
either tables or graphs form, and with the methodology of analysing the data.
(b) Inferential Statistics - It involves techniques for making inferences about the whole
population on the basis of observations obtained from samples.
1.2 Some Basic Definitions
(a) Population - A population is the group from which data are to be collected.
(b) Sample - A sample is a subset of a population.
(c) Variable - A variable is a feature characteristic of any member of a population
differing in quality or quantity from one member to another.
(d) Quantitative variable - A variable differing in quantity is called quantitative variable,
for example, the weight of a person, number of people in a
car.
(e) Qualitative variable - A variable differing in quality is called a qualitative variable or
attribute, for example, color, the degree of damage of a car in
an accident.
(f) Discrete variable - A discrete variable is one which no value may be assumed
between two given values, for example, number of children in a
family.
(h) Continuous variable - A continuous variable is one which any value may be assumed
between two given values, for example, the time for 100-meter
run.