Study excerpt: Macartney and colleagues (2018) studied the concussion symptoms in 136 adolescents, 74 female and 62 male. "A retrospective chart review was completed between 11/ 21/ 2014 to 11/ 20/ 2015. A purposive sample of all patients who visited the CHEO [Children's Hospital of Eastern Ontario] concussion clinic during the study period [was] included. Patients were excluded if symptoms records were not documented... CHEO's concussion clinic opened in the fall of 2014. The clinic provides care to patients less than nineteen years old who remain symptomatic at least four weeks post injury."

For each question that includes an excerpt about sampling from a research article, provide the following information: (1) decide whether the sampling method presented is either a probability or nonprobability sampling method; (2) identify the specific sampling method used that is, convenience, quota, purposive, network, or theoretical sampling for nonprobability samples or simple random, stratified random, cluster, or systematic sampling for probability samples (see Table 2-1); and (3) provide a rationale for the sampling method you selected. Some of the examples might include more than one sampling method to obtain the study sample.

TABLE 2-1 PROBABILITY AND NONPROBABILITY SAMPLING METHODS Sampling Method Common Application( s) Representativeness of Sample or In-depth, Richness of Findings to Promote Understanding Probability Simple random sampling Quantitative research Strong representativeness of the target population that increases with sample size. Stratified random sampling Quantitative research Strong representativeness of the target population that increases with control of stratified variable( s). Cluster sampling Quantitative research Less representative of the target population than simple random sampling and stratified random sampling, but representativeness increases with sample size. Systematic sampling Quantitative research Less representative of the target population than simple random sampling and stratified random sampling methods, but representativeness increases with sample size. Nonprobability Convenience sampling Quantitative, qualitative, and mixed methods research Questionable representativeness of the target population that improves with increasing sample size. Used in qualitative and mixed methods research so adequate participants might be found to promote understanding of the study area.snowball sampling Qualitative and mixed methods research and sometimes quantitative research Focus is on insight, description, and understanding of a phenomenon, situation, process, or cultural element in a difficult-to-access population. Theoretical sampling Qualitative research Focus is on developing a theory in a selected area with specially selected study participants.

there is no missing information.