Describe Variable in Brief

Variable

As the information of a particular characteristics vary from unit to unit, is called variable. Variable is two types. viz (a) Qualitative Variable, (b) Quantitative Variable.

Qualitative Variable

The variable which can not normally be measured by numerical figure is known as qualitative variable. For example, occupation of a person, types of disease of patient, qualification of doctor, rank of a doctor, rank of a nurse, etc. The qualitative variable is also known as attribute.

Quantitative Variable

The variable which is measured by numerical figure is known as qualitative variable. For example, age of patient, height of patient, weight of patient, blood pressure level of patient, blood sugar level of patient, duration of disease of patient, number of patients admitted in different days, etc. 

The Quantitative Variable is of two types, viz (a) Discrete Variable, (b) Continuous Variable.

Discrete Variable

The variable which is measured only by integral value is known as discrete variable. For example, number of ever born children of mothers, number of dead children of mothers, number of patients admitted in days in hospital, number of doctors/nurse working in hospitals etc.

Continuous Variable

The variable which is measured by integral as well as by fractional values is known as continuous variable. For example, age of patients, weight of patients, height of patients, blood sugar levels of patients etc.

The variable discrete and continuous may again be classified as (i) Random Variable , (ii) Non Random Variable

Random Variable

If the values of a variable are observed from different units selected by random process, than the variable is known as random variable. For example, let there be N=500 patients in a hospital and n=100 patients are selected by a random process for investigation. In that case variable is observed from those selected 100 patients, then it will be random variable.

Non-random Variable 

If variable is observed from all units in the population, then it is known as non-random variable.