# Some Basic Definitions in Statistics

**Constant**

A quantity which can assume only one value is called a constant. It is usually denoted by the first letters of the alphabet, $$a,b,c$$.

**For example:** The value of $$\pi = \frac{{22}}{7} = 3.14159…$$ and the value of $$e = 2.71828…$$.

**Variable**

A quantity which can vary from one individual or object to another is called a variable. It is usually denoted by the last letters of the alphabet, $$x,y,z$$.

**For example:** Heights and weights of students, income, temperature, number of children in a family, etc.

**Continuous Variable**

A variable which can assume each and every value within a given range is called a continuous variable. It can occur in decimals.

**For example: **Heights and weights of students, speed of a bus, the age of a shopkeeper, the life time of a T.V, etc.

**Continuous Data**

Data which can be described by a continuous variable are called continuous data.

**For example:** Weights of 50 students in a class.

**Discrete Variable**

A variable which can assume only some specific values within a given range is called a discrete variable. It cannot occur in decimals; it can only occur in whole numbers.

**For example:** Number of students in a class, number of flowers on a tree, number of houses on a street, number of chairs in a room, etc.

**Discrete Data**

Data which can be described by a discrete variable are called discrete data.

**For example:** Number of students in a college.

**Quantitative Variable**

A characteristic which varies only in magnitude from one individual to another is called a quantitative variable. It can be measurable.

**For example:** Wages, prices, heights, weights, etc.

**Qualitative Variable**

A characteristic which varies only in quality from one individual to another is called a qualitative variable. It cannot be measured.

**For example:** Beauty, marital status, rich, poor, scent, etc.