Question

Sampling Method The patients included in the study cited in Exercise 1 were those “who sought care for low-back pain directly or in response to a community advertisement.” What type of sampling best describes the way in which the 1643 subjects were chosen: simple random sample, systematic sample, convenience sample, stratified sample, cluster sample? Does the method of sampling appear to adversely affect the quality of the results?

Short answer

The sampling method is convenience sampling, and it does not have any adverse effect on the result’s quality.

Step-by-step solution

Given information

The number of patients in the study is 1643,“who sought care for low-back pain directly or in response to a community advertisement.”

The 1643 patients are assigned one of the following treatments:

Treatments	Size	Type
1.	547	Placebo
2.	550	Regular intervals pills.
3.	546	Pills when required.

Type of sampling method

The sampling method is determined by identifying the technique of selecting the subjects. In the study, the patients are selected using convenience sampling.

In convenience sampling, the subjects are chosen by the simplest methodology, i.e., as per the convenience of the researcher. In the study, the patients were selected by approaching a group who sought care directly or responded to some advertisement.

The effect of sampling on the quality of results

In a general sense, convenience sampling has a huge potential to provide biased results.

However, in this study, the three treatments are appropriate factors for the study, each acquiring responses from a large number of subjects.

Thus, despite the convenience sampling, the chances of bias are low, and hence results would not be greatly affected.