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• Sampling


  In research, sampling is a word that refers to your method or process of selecting respondents or people to answer questions meant to yield data for a research study.
• Population


  The bigger group from where you choose the sample size
• Sample size


  A representation of a bigger population
• Beginning of sampling could be traced back to the early political activities of the American when Literary Digest did a pioneering survey about the American citizens' favorite among the 1920 presidential candidates


  Early 1920s
• Sampling Strategies


  • Probability Sampling
  • Non-Probability Sampling
• Slovin's formula


  n=N/(1+Ne)^2, where n = sample size, N = population, e= sampling error
• Slovin's formula: Round off, don't round down
• Sampling frame


  Involves all members listed representing the population focused on by your study
• Types of Probability Sampling

  • Simple Random Sampling (the best type of probability sampling. Using a pure-chance selection)
  • Systematic Sampling (chance and system are the ones to determine who should compose the sample.)
  • Stratified Sampling (The group comprising the sample is chosen in a way that such group is liable to subdivision during the data analysis stage.)
  • Cluster Sampling (This is a probability sampling that makes you isolate a set of persons instead of individual members.)
• Non-Probability Sampling


  Disregards random selection of subjects, subjects are chosen based on availability or purpose of study, and sometimes at the sole discretion of the researcher
• Non-probability sampling is not a scientific way of selecting respondents, neither does it offer a valid or an objective way of detecting sampling errors
• Types of Non-Probability Sampling

  • Quota Sampling
  • Voluntary Sampling
  • Purposive or Judgmental Sampling
  • Availability or Convenience Sampling
  • Snowball Sampling
• Quota Sampling


  You choose sample members possessing or indicating the characteristics of the target population when you think you know the characteristics of the target population very well
• Voluntary Sampling


  The subjects you expect to participate in the sample selection are the ones volunteering to constitute the sample, so there is no need for you to do any selection process
• Purposive or Judgmental Sampling


  You choose people whom you are sure could correspond to the objectives of your study, like selecting those with rich experience or interest in your study
• Availability or Convenience Sampling


  The willingness of a person as your subject to interact with you counts a lot, if you encounter people during data collection who show willingness to respond, you automatically consider them as your respondents
• Snowball Sampling


  Similar to snow expanding widely or rolling rapidly, this sampling method does not give a specific set of samples, it is useful for studies involving unspecified groups of people like street children, mendicants, drug dependents, etc.