Problem 14BSC
identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.
Acupuncture Study In a study of treatments for back pain, 641 subjects were randomly assigned to the four different treatment groups of individualized acupuncture, standardized acupuncture, simulated acupuncture, and usual care (based on data from “A Randomized Trial Comparing Acupuncture, Simulated Acupuncture, and Usual Care for Chronic Low Back Pain,” by Cherkin et al., Archives of Internal Medicine, Vol. 169, No. 9).
Problem 14BSC
Answer:
Step1 of 3:
We have In a study of treatments for back pain, 641 subjects were randomly assigned to the four different treatment groups of individualized acupuncture, standardized acupuncture, simulated acupuncture, and usual care (based on data from “A Randomized Trial Comparing Acupuncture, Simulated Acupuncture, and Usual Care for Chronic Low Back Pain,” by Cherkin et al., Archives of Internal Medicine, Vol. 169, No. 9).
Step2 of 2:
We need to identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.
Step3 of 3:
Let us understand what are the types of sampling
Consider,
1).simple random sample: A simple random sample is a subset of a statistical population in which each member of the subset has an equal probability of being chosen.
2).Systematic sample:Systematic random sampling is the random sampling method that requires selecting samples based on a system of intervals in a numbered population.
3).Convenience: A convenience sample is one of the main types of non-probability sampling methods. A convenience sample is made up of people who are easy to reach.
4).Stratified: Stratified is a probability sampling technique wherein the researcher divides the entire population into different subgroups or strata, then randomly selects the final subjects proportionally from the different strata.
5).Cluster: Cluster sampling refers to a type of sampling method . With cluster sampling, the researcher divides the population into separate groups, called clusters. Then, a simple random sample of clusters is selected from the population. The researcher conducts his analysis on data from the sampled clusters.
This is a “stratified sample” because, the acupuncture subjects were split into different groups based on the different types of acupuncture (strata). Then the subjects in the separate strata were compared to see the effects each type of acupuncture had on chronic lower back pain.
