American Association for Cancer Research

Table 4

KRAS mutation frequency by age at diagnosis, smoking history, and sex

A. Variable	Mean	SD	P
Age at diagnosis
No KRAS mutation	60.6 yrs	9.8	0.123^a
KRAS mutation	57.5 yrs	8.6
Smoking history
No KRAS mutation	64.2 pack-years	44.5	0.084^b
KRAS mutation	51.3 pack-years	31.3

A. Variable	Mean	SD	P
Age at diagnosis
No KRAS mutation	60.6 yrs	9.8	0.123^a
KRAS mutation	57.5 yrs	8.6
Smoking history
No KRAS mutation	64.2 pack-years	44.5	0.084^b
KRAS mutation	51.3 pack-years	31.3

B. Sex	Male	Female	P
No KRAS mutation	56	28	0.591^c
KRAS mutation	23	9

Pooled t test for equal variances.

Satterthwaite t test for unequal variances (folded F-test for variances, P = 0.0298).

χ² goodness-of-fit analysis with 1 DF.