(4) Sampling Procedure and the Sample

Cards (22)

  • population - the totality of all the objects, elements, persons, and characteristics under consideration
  • population - it is understood that this population possesses common characteristics about which the research aims to explore
  • two types of population
    1. target population
    2. accessible population
  • actual population - the target population
  • accessible population - the portion of the population in which the researcher has reasonable access
  • sample - when the population is too costly or time-consuming or impractical to consider, a representative is identified
  • sampling - pertains to the systematic process of selecting the group to be analyzed in the research study
  • sample - the goal is to get information from a group that represents the target population
  • a good sample should have characteristics of the represented population- characteristics that are within the scope of the study with fair accuracy
  • approaches in identifying the sample size:
    1. heuristics
    2. literature review
    3. formulas
    4. power analysis
  • heuristics - this approach refers to the rule of thumb for sample size
  • research design [no.of subjects/participants]
    descriptive - 10% to 20%
    comparative research - 15 subjects/ groups
    survey- 800
    correlational- 100-200
    ex post facto - 30+
    experimental - 30/more
  • literature review - this approach is by reading similar/ related literature and studies to your current research study. Using this approach increases the validity of your sampling procedure.
  • formulas - being established for the computation of an acceptable sample size. The common one is Slovin's Formula.
  • Slovin's Formula - n=N/1+Ne^2
  • power analysis - this approach is founded on the principle of power analysis. There are two principles you need to consider if you are going to use this approach: statistical power and effect size.
  • statistical power - the probability of rejecting the null hypothesis.
  • statistical power - it suggest that there is a relationship between the independent and dependent variables of the research study.
  • statistical power - It will be used to identify the sufficient sample size for measuring the effect size of a certain treatment.
  • effect size - the level of difference between the experimental group and the control group
  • if the statistical power tells that relationship between independent and dependent variables, the effect size suggests the extent of the relationship between these two variables.
  • once a good sample is obtained, the generalizability and applicability of findings increase