Why is matching done in a case‐control study?
1. To remove the effect of known confounders
2. To remove the effect of unknown confounders
3. To eliminate selection bias
4. To eliminate interviewer’s bias
Select the correct answer using the code given below:
(a) 1 only
(b) 2 and 3
(c) 1, 3 and 4
(d) 4 only