HEOC 715: Sampling & Participants. How Sampling Affects Research. Collecting Quantitative Data: Probability Sampling: First Step. Whom will you study? Individuals, entire organizations, both? (i.e., Identify your unit of analysis)
How Sampling Affects Research
Above illustrates … Probability Sampling, i.e., every member of the population has an equal chance of being selected.
Above illustrates nonprobability sampling: i.e., nonrandom procedures are used for selecting individuals in the sample. Process driven by availability, , convenient and compatibility with the study.
Which type of study uses nonprobability sampling (Quantitative or Qualitative) and why?
Alternative Sampling Methods:
School District Administrators plans to study parent satisfaction. Selects a % of the parents to study, i.e., 20%. Given 1000 parents, 200 (or 20%) would be studied. The administrator uses intervals of 5 (200/1000, or 1 out of 5 parents) from the target mailing list. Every 5th parent is surveyed.
Alternative Sampling Methods:
For ex.: If you are studying opinions on a specific political issue, you would divide the population in subgroups based on what? Why?
For ex., it’s very difficult to study a sample scattered across the US; or a target population of American high schools students which is too large to list and draw a sample.
1. a. Quantitative: participants and sites systematically identified with random sampling;
b. Qualitative: participant and site selections based on subjects and places that best inform the phenomena under study;
2.a. Both require permissions to begin a study;
b. Qualitative needs greater access to a site to garner information, observe participants and record data;
c. Quantitative process requires less participation at the site, which varies based on the type of research interests being studied.
3. a. Both collect data, e.g., interviews, observations, documents;
b. Qualitative research relies on general interviews or observations, encourages participants to share their viewpoints, utilizes open-ended quesitons;
c. Quantitative research uses standardized instruments and collects closed-ended, objective information.
4.a. Both approaches record information provided by participants;
b. Qualitative research record information on self-developed protocols, which provide a venue for organizing participants’ responses to each question;
c. Quantitative research uses predesigned instruments with defined procedures and operational standards.
5. a. Qualitative researchers are sensitive to the challenges and ethical issues involved in collecting information face-to-face in a variety of sites, e.g., people’s homes or in the workplace.
b. Quantitative researchers utilize objectives measures that follow a prescribed process and include such tools as anonymous questionnaires and standardized observational checklists designed to ensure reliable results.
How would you know that convenience sampling was used in a study?
In what type of research would convenience sampling be most informative?
How would you select a sample of 40 college students for a morale study from a freshman class of 320?
A sociologist plans to research the effect of a regimented exercise program on the weight loss of ten people who completed the entire program at a local health club. The researcher plans to interview the participants about their program, and will record responses relative to the amount of weight loss and any additional open-ended testimonials provided.