Summary: This module introduces an independent variable, gives example of such variables and an exercise.

An independent variable is that variable which is presumed to affect or determine a dependent variable. It can be changed as required, and its values do not represent a problem requiring explanation in an analysis, but are taken simply as given [Wikipedia2006I].

More generally, the independent variable is the thing that someone actively changes; while the dependent variable is the thing that changes as a result.

The wages of an employee depend on the time worked. Time is the independent variable that varies among employees, and the wages are calculated directly from the total time worked. Thus wages are dependent on time worked. [taken from Wikipedia2006I]

In a call centre, the number of customers serviced per hour, depends on the number of agents, and average service time per customer. In this case number of customers is a dependent variable, entirely dependent on the other two independent variables namely agents, and average service time.

What is an independent variable in the following function? Briefly explain your choice.

Y = 3X + Z - 5

There are two independent variables namely X, and Z. This is because their values can change freely regardless of the value of X, and that change is going to affect X as a result.

References:

- Wikipedia2006I. "
*Independent Variable*," http://en.wikipedia.org/wiki/Independent_variable, Last Accessed on 20 February 2006 - Author of Assignment 3: Lekulana Kolobe
- Author of Assignment 1: Arnold Mwesigye