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Nursing 360: Sampling Methods and Statistics

Resources and tutorials for NURS 360

Sampling Methods

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

Nursing Planet

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

Instruments in Nursing Research

  • 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).

Difference Between "Population" and "Sample"

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.

Data Collection Methods

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