(Single Best Answer) Question 21: A village has a total of 100 under-five children. The coverage with measles vaccine in these age groups is 60%. Following the occurence of a measles case in a child after a visit outside, twenty six children developed measles later. The secondary attack rate of measles is ?
A) 16.6% B) 26.0% C) 65.0% D) 66.6% Answer (Select an option above to get the answer):
A) 12 months B) 15 months C) 24 months D) 36 months Answer (Select an option above to get the answer):
(Single Best Answer) Question 23: What is the method of sampling in which the units are picked up at regular intervals from the universe ?
A) Simple random sampling B) Systematic random sampling C) Stratified random sampling D) Snow-ball sampling Answer (Select an option above to get the answer):