
Chapter 15
PB
Multiple Regression Analysis
593
a non-linear relationship into a linear relationship. If we compare Figure 15.48 (Minitab output for
Example 15.4 in case of linear regression) with Figure 15.49 (Minitab output for Example 15.4 in
case of transformation of x variable), we nd that the model after transformation is slightly bet-
ter than the model before transformation. It can be seen that the value of R
2
and adjusted R
2
has
increased and standard error has decreased in the transformed model. Table 15.9 shows the number
of defects in 12 lots with different batch sizes with square root transformation of batch size.
FIGURE 15.46
Minitab ...