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:10.1186/14712407665 