What is a linear model?

Hi Helen,

We usually think of a model of some system as a device that duplicates or approximates the behavior of the system. A mathematical model is a collection of equations or inequalities that acts as a model. A linear model is one where the equations or inequalities involve linear functions only. Linear models are used quite often in statistics. For example, can you find a linear model that will predict a university student's grade point average at the end of his or her first year (Y) from the score on an entrance exam (X)? To do this you would probably try to find a linear model, that is an equation of the form Y = a + bX that will approximate the actual situation.

I hope this helps,
Harley