S138 Chapter 1 (Terminologies)

• Target Population - the population of interest; the totality of all units in consideration of the context of the study
• Sample - a subset of a population
• Census - if the whole population is a sample
• Sampled Population - a collection where we get our samples
• Sampling Unit - the content of the sampled population
• Sampling Frame - a list of units in our sampled population
• Observation Unit - this is where we get or extract the information needed
• Selection Bias - a bias due to not taking into account all of the population in consideration of the study or containing more elements that are not part of the interest
• Measurement Error

  • When interviewees do not tell the truth
  • When translations are interpreted differently
  • Characteristics of the interviewer
  • Questions are too complicated
• Estimation Bias - the technical bias we know from inference
• Sampling Error - error because we are sampling; sample is not representative of the whole population
• Nonsampling Error - does not depend on the sampling; will always persist