Table 6

Comparisons of linear regression models, with and without outlier, of the natural logarithm of the rate of stomach cancer on the main explanatory variables. The difference between the residual sum of squares (RSS) before and after each explanatory variable had been added to regression (ΔRSS) was divided by RSS and multiplied by the error df to yield F, whose numerator df was 1 and denominator df was the error df.

WITHOUT OUTLIER


Model Covariates

RSS

ΔRSS

error df

F

P


Null

403.26

five year period

402.96

0.30

157

0.1

0.73

five year period + sex

388.32

14.64

156

5.9

0.02

five year period +sex + race

319.23

69.09

155

33.5

3.8 × 10-8

five year period + sex + race + Lauren type

255.93

63.30

154

38.1

5.7 × 10-9

five year period + sex + race + Lauren type + age

50.64

205.29

153

620.2

< 1 × 10 -10

WITH OUTLIER

Model Covariates

RSS

ΔRSS

error df

F

P

Null

437.81

five year period

436.79

1.02

158

0.4

0.54

five year period + sex

418.50

18.29

157

6.9

0.01

five year period +sex + race

342.38

76.12

156

34.7

2.3 × 10-8

five year period + sex + race + Lauren type

273.23

69.15

155

39.2

3.5 × 10-9

five year period + sex + race + Lauren type + age

58.14

215.10

154

569.8

< 1 × 10 -10


Wachtel et al. BMC Cancer 2006 6:65   doi:10.1186/1471-2407-6-65

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