Statistics V3

• Non-probability Sampling


  Does not rely on the use of randomization techniques to select members. It is one where not all elements in the population frame have an equal chance of being selected.
• Convenience or Accidental sampling


  • Sampling strategy based on the convenience of the researcher
  • Members or units are selected based on availability
• Purposive sampling


  • Members of a particular group are purposefully sought after
  • The researcher uses his good judgment in selecting the respondents who best meet the purpose of his study
  • Also known as judgemental sampling
• Snowball sampling


  • Requires identification of a few persons who met the requisite characteristics important to the study
  • These persons act as informants to identify others who qualify for inclusion in the sample, who in turn lead to more persons who can be interviewed
  • The process continues until the desired number of respondents is reached
  • The term "snowball" stems from the analogy of a snowball which begins small but becomes bigger and bigger as it rolls down the hill
• Quota sampling


  • You identify a set of important characteristics of a population and then select your desired samples in a non-random way
  • It is assumed that the samples will match the population with regard to the chosen set of characteristics