Question

categorize the type of sampling (simple random, stratified, systematic, cluster, or convenience) used in each of the following situations.
(a) to conduct a pre - election opinion poll on a proposed amendment to the state constitution, a random sample of 10 cell phone prefixes (first three digits of the phone number) was selected, and all households from the phone prefixes selected were called.
simple random sample
stratified sample
systematic sample
cluster sample
convenience sample
(b) to conduct a study on depression among the elderly, a sample of 30 patients in one nursing home was used.
simple random sample
stratified sample
systematic sample
cluster sample
convenience sample
(c) to maintain quality control in a brewery, every 20th bottle of beer coming off the production line was opened and tested.
simple random sample
stratified sample
systematic sample
cluster sample
convenience sample

Explanation:

(a) Phone prefixes are clusters, so it's cluster sampling. (b) Using patients from one nursing - home is convenient, so convenience sampling. (c) Selecting every 20th bottle is systematic sampling.

Answer:

(a) cluster sample
(b) convenience sample
(c) systematic sample