10

54

54

115

11

63

67

118

12

76

99

132

13

60

74

111

14

61

73

112

15

65

85

147

16

79

80

138

Looking at Table 17-2, let’s assume that your variable names are StudyID for Participant ID, Age for

age, Weight for weight, and SBP for SBP. Imagine that you’re planning to run a regression model with

this formula (using the shorthand notation described in the earlier section “Defining a few important

terms”): SBP ~ Age + Weight. In this case, you should first prepare several scatter charts: one of SBP

(outcome) versus Age (predictor), one of SBP versus Weight (another outcome versus predictor), and

one of Age versus Weight (both predictors). For regression models involving many predictors, there

can be a lot of scatter charts! Fortunately, many statistics programs can automatically prepare a set of

small thumbnail scatter charts for all possible pairings among a set of variables, arranged in a matrix

as shown in Figure 17-1.

© John Wiley & Sons, Inc.

FIGURE 17-1: A scatter chart matrix for a set of variables prior to multiple regression.