Disease data for two independent groups are summarized into

Disease data for two independent groups are summarized into 2 by 2 tables stratified by gender. Based on Mantel-Haenszel procedure, the Mantel-Haenszel summary relative risk ratio is 1.6 and the crude relative risk ratio 1.5, the gender variable is

1)Positive confounders

2)Negative confounders

3)Can not be determined

Solution

ositive confounders

because the relative risk ratio are greater than 1