Table 6. Comparisons among different statistical tests for testing independence between stage at initial diagnosis and response to treatment in a previously treated lung cancer patient population (modified data from Example 2).

Methods	P value	Clinical interpretation
Chi-squared test	<0.01	Initial diagnosis stage is significantly associated with response rate
Gamma statistics	0.09	No statistically significant evidence of monotone trend in response rate as the initial diagnosis stage advances
Cochran-Armitage trend test	0.32	No statistically significant evidence of linear trend in response rate as the initial diagnosis stage advances
Logistic regression (fitting stage as nominal variable)	Stage I vs. IV: 0.23	Compared with stage IV, stage III, but neither stage I nor II, has significantly higher likelihood to respond to the treatment
	Stage II vs. IV: 0.06
	Stage III vs. IV: 0.01