ABSTRACT
Chapter 8 introduced the technique of regression analysis as a means of describing and analysing the relationship between a response variable and an explanatory variable. However, in many real-life situations more than one explanatory variable could be used to predict the response variable. For instance, the salary example in Section 8.1 has two explanatory variables, age and qualification score, both of which could be used to predict salary. Likewise, in the ice cream example, sales may depend not only on daily temperature but also on, for example, the price of the product and the monthly advertising expenditure. Thus we could be looking at a regression analysis that involves up to three explanatory variables. In the moisture content example we could also consider ambient temperature, processing time, and the storage time of the raw material as additional explanatory variables.
