QUESTION 1 Marshall randomly selected 250 students from a large university to study their use of drugs and alcohol A Probability B Nonprobability QUESTION 2 Casey randomly assigned 152 elders recruited from five nursing homes to a foot massage or wait-list group to assess effects on levels of depression A Nonprobability B Probability QUESTION 3 Kendall randomly assigned postsurgical patients to aromatherapy (oil of pepermint) or usua care, to assess effects on nausea A Experimental B Nonexperimental C Quasi-experimental

QUESTION 1: Marshall randomly selected 250 students from a large university to study their use of drugs and alcohol. Is this an example of probability or nonprobability sampling?

The study described where Marshall selected 250 students from a large university to study their use of drugs and alcohol is an example of probability sampling. In probability sampling, every member of the population has a known chance of being selected for the study. In this case, each student enrolled in the university had an equal chance of being chosen to participate in the study. By randomly selecting the participants, Marshall ensured that the sample represented the broader population of students at the university.

Probability sampling methods are considered ideal for research as they provide researchers with a sample that is representative of the target population. This allows for generalizations to be made from the study results to the larger population.

QUESTION 2: Casey randomly assigned 152 elders recruited from five nursing homes to a foot massage or wait-list group to assess effects on levels of depression. Is this an example of probability or nonprobability sampling?

The study described where Casey randomly assigned 152 elders recruited from five nursing homes to a foot massage or wait-list group is an example of probability sampling. In this case, the sample of elders was selected from specific nursing homes using a random assignment process. Each elder had an equal chance of being assigned to either the foot massage or wait-list group. By randomly assigning the participants, Casey ensured that the groups were comparable at the start of the study, increasing the internal validity of the research.

It is important to note that while random assignment is a component of probability sampling, it does not necessarily guarantee that the overall sample is representative of the broader population. In this case, the sample is representative of the elders recruited from the five nursing homes, but generalizations to the larger population of elders cannot be made without considering the sampling frame.

QUESTION 3: Kendall randomly assigned postsurgical patients to aromatherapy (oil of peppermint) or usual care to assess effects on nausea. Is this an example of experimental, nonexperimental, or quasi-experimental design?

The study described where Kendall randomly assigned postsurgical patients to aromatherapy (oil of peppermint) or usual care is an example of an experimental design. Experimental designs involve manipulating an independent variable (in this case, the use of aromatherapy) and observing the effects on a dependent variable (nausea levels).

By randomly assigning the postsurgical patients to either the aromatherapy or usual care group, Kendall ensured that the groups were comparable at the start of the study. This random assignment increases the internal validity of the research as it helps control for potential confounding variables. The use of random assignment allows for stronger causal inferences to be made about the effects of aromatherapy on nausea.

It is worth noting that the study design described could also be considered quasi-experimental. Quasi-experimental designs lack random assignment, but still involve the manipulation of an independent variable. In this case, if Kendall had selected patients based on pre-existing conditions or non-random criteria, the design would be considered quasi-experimental. However, the random assignment to groups makes it an experimental design.

In conclusion, Marshall’s study of student drug and alcohol use utilized probability sampling, Casey’s study on depression in elders involved probability sampling, and Kendall’s evaluation of aromatherapy’s effect on nausea followed an experimental design. These considerations regarding sampling and research design are essential for ensuring the validity and reliability of research findings.