If changes in the level of factor A result in different changes in the value of the response variable for different levels of factor B, we say there is an ____________.
Step 1 of 5) If changes in the level of factor A result in different changes in the value of the response variable for different levels of factor B, we say there is an If there are two explanatory variables, model (1) reduces to yi = b0 + b1x1i + b2x2i + ei (2) If there are three explanatory variables, model (1) reduces to yi = b0 + b1x1i + b2x2i + b3x3i + ei (3) Because we typically do not have access to population data, the parameters, b0, b1, b2, and so on, must be estimated using sample data. Let b0 represent the estimate of b0, b1 represent the estimate of b1, and so on. Although formulas do exist for determining the values of b0, b1, c, bk, they are beyond the scope of this text. Therefore, we will be content to obtain estimates of the parameters using statistical software, such as Minitab, Excel, or StatCrunch. In obtaining a multiple regression model, we must decide which variables to include in the model and which to exclude. One tool that will aid us in this decision is the correlation matrix.
