Example 11. Logistic Regression: Health Data

The health status of a sample of 32 subjects is measured as a binary response variable (0=healthy and 1=unhealthy). Explanatory variables are values of plasma fibrinogen and gamma-globulin (measured in gm/liter).

Source: Collett, D.R. (1991). Modeling Binary Data. Chapman & Hall: London.

Table 11: Health Data

 1 2.52 38 0  2 2.56 31 0  3 2.19 33 0  4 2.18 31 0
 5 3.41 37 0  6 2.46 36 0  7 3.22 38 0  8 2.21 37 0
 9 3.15 39 0 10 2.60 41 0 11 2.29 36 0 12 2.35 29 0
13 5.06 37 1 14 3.34 32 1 15 2.38 37 1 16 3.15 36 0
17 3.53 46 1 18 2.68 34 0 19 2.60 38 0 20 2.23 37 0
21 2.88 30 0 22 2.65 46 0 23 2.09 44 1 24 2.28 36 0
25 2.67 39 0 26 2.29 31 0 27 2.15 31 0 28 2.54 28 0
29 3.93 32 1 30 3.34 30 0 31 2.99 36 0 32 3.32 35 0

Questions:

1. Fit a binary logistic regression model of response on the explanatory variables.

Keywords: Logit transformation, link function