- Briggs Library
- LibGuides
- Nursing 360
- Sampling Methods and Statistics

Resources and tutorials for NURS 360

**Random (Probability) sampling **

- A selection process that ensures each participant the same probability of being selected.
- The best method for ensuring that a sample is representative of the larger population.
- Random sampling can be:
- simple random sampling
- stratified random sampling, or
- cluster sampling

**Nonprobability sampling**

- The probability that any one individual or subject is selected is not equal to the probability that any other individual or subject may be selected.
- Probability of inclusion and the degree to which the sample represents the population are unknown.
- Major problem is that sampling bias can occur.
- Nonprobability sampling can be:
- convenience sampling
- purposive sampling, or
- quota sampling

- Open access articles on nursing research.
- Includes practice quizzes on many aspects of research: sampling, statistics, study designs, etc.

- An instrument in a research study is a device used to measure the concept of interest in a research project.
- An ideal measuring instrument is one which results in measures that are relevant, accurate, objective, sensitive and efficient.
- Measures which are physical and physiological have higher chance of success in attaining these goals than measures that are psychological and behavioral.
- Instruments may be:
- observation scales
- questionnaires, or
- interview schedules

- Validity and reliability are two statistical properties used to evaluate the quality of research instruments
- It is important that assessment techniques possess both validity and reliability (Anastasi, A. 1986.
*Psychological testing.*NY: Macmillan).

While "population" is about the generality of the universe or groups of people, "sample" refers to a fraction of persons from the population.

It is from the sample that data are collected in the course of a study, and if that sample is representative of the population, the results can be generalized to the population in a scientific study.

**Statistics Made Easy (8-part video series)**

- See especially Parts 1, 3, 4.