Question

A study of 178 cases of disease X were identified from a state registry. A total of 220 control subjects were then recruited from random-digit dial procedure. 16 cases had been exposed, compared to only 8 controls. How likely were cases to report an exposure compared with controls

Answer 1

2.47 times more likely.

Explanation:

16 out of 178 cases were reported for exposure.

And 8 out of 220 control reported for exposure.

Chances that a case would be reported for exposure = (16/178) = 0.0898876404

Chances that one control would report for exposure = (8/220) = 0.0363636364

Comparing both, how likely were cases to report an exposure compared with controls

= (0.0898876404) ÷ (0.0363636364)

= 2.4719101085 = 2.47 times more likely.

Hope this Helps!!