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• 1 Threats to Internal Validity

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• What are the 3 threats to internal validity due to participants? And what are the characteristics

  - Maturation (natural change)
  - Selection (systematic differences in participant characteristics)
  - Selection by maturation (when groups systematically differ in their rate of natural change (maturation))

• What are the 3 threats to internal validity due to instruments? And what are the characteristics?

  - Low construct validity (when instruments contain a systematic bias or measure another construct)
  - Instrumentation (instruments change during the course of the study)
  - Testing (measurements affect the subject's behavior)

• What are the 2 threats to internal validity due to instruments? And what are the characteristics?

  - Experimenter expectancy (biasing effect of the researcher's expectations, unconsciously)
  - Demand characteristics (biasing effect of participant's expectations)

• What are the 3 threats to internal validity due to research set-up? And what are the characteristics?

  - Ambiguous temporal precedence (when its unclear if the hypothesized cause actually precedes the effect)
  - History (small or large-scale event that can provide an alternative explanation, unforeseen)
  - Mortality (drop-out during the study, which can provide an alternative explanation

• Name three types of longitudinal studies and its characteristics

  - Trend study (a type of study in which a given characteristic of some population is monitored over time)
  - Cohort study ( a study in which a researcher examines specific subpopulations, or cohorts, as they change over time. All share a characteristic)
  - Panel study (a study in which data are collected from the same set of people at several points in time)

• What is a cross-sectional study? And what are any problems and solutions?

  - Involves observations of a sample, or cross-section, of a population of phenomenon that are made at one point in time.
  - Problem: Generalization about social-life from a 'snapshot' often is not applicable
  - Solution: Revisit phenomena and build on the results of earlier researcher

• What is the difference between cross-sectional and longitudinal studies?

  Longitudinal studies have an advantage over cross-sectional ones in providing information describing processes over time. This comes at a heavy cost in both time and money.

• "Smoking causes depression" - What is the independent variable and the dependent variable?

  Smoking = Independent variable
  Depression = Dependent variabla

• What are the three components that are usually in a classical experiment?

  1 Independent and dependent variables
  2 Pretesting and posttesting 
  3 Experimental and control groups

• What are the three essential ingredients of true experiments?

  1. Manipulation
  2. Comparison
  3. Randomization