Random Variable
- a variable that assigns a numerical value to each outcome of a random event.
- It can be classified as discrete or continuous -depending on whether the value is obtained by
counting or by measurement.
Discrete Variable – a quantitative variable whose value can only be attained through
counting. It is measured as whole
numbers of units.
Example:
 The number of children in a family
 Flipping a coin
 When you flip a coin several times and count the
number of heads. The number of heads could be any
whole number value. We could get the numbers 0,1,2,3,
and so on.
 Therefore, the number of heads when flipping a coin is a
discrete variable
Discrete Random Variable – if the experiment has only countable infinite number of
outcomes.
Continuous Variable – a quantitative variable that can assume an infinitely many,
uncountable number of real number values.
Example:
 distance traveled by a vehicle
 exact age of a person
 height of a person
Continuous Random Variable – an outcome of an experiment that take an uncountably
infinite number of possible outcomes within a specified real number interval.
Example:
 height of an employee