A radio advertiser wishes to choose a sample of size 100 from a population of 5000 listeners.

1. A radio advertiser wishes to choose a sample of size 100 from a population of 5000 listeners. After observing that 5, 000 ÷ 50 = 100, he first selects a subject at random from the first 50 names in the sampling frame, and then he selects every 50th subject listed after that one. This method of sampling is called: 

A) Stratified random sampling.

(B) Simple random sampling.

(C) Cluster random sampling.

(D) Systematic random sampling. 

A radio advertiser wishes to choose a sample of size 100 from a population of 5000 listeners. He divides the population into five separate groups and then selects a simple random sample from each group. This method of sampling is called:

(A) Simple random sampling.

(B) Systematic random sampling.

(C) Cluster random sampling.

(D) Stratified random sampling.