In a village every fifth house was selected for a study. This is an example of -: (A) Simple random sampling, (B) Systematic random sampling, (C) Stratified random sampling, (D) Convenience sampling
Answer is B. Systematic random sample: this is done by picking every 5th and 10th unit at regular intervals. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 913