Measuring and Manipulating Variables

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Measuring and Manipulating Variables
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Sources of Error in Research

• Researchers
• Experimenter (_______) Bias
• Experimenters ________ or personal beliefs can
  _________ results
• Ways to control for this bias
• __________ procedures for data collection
• _______ -Blind study researcher doesnt know
  predicted outcome
• _________ -Blind study researcher and
  ___________ are unaware of predicted outcome

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Sources for Error in Research

• Participants
• ________ Desirability
• Participants respond in way that makes them look
  _______ (socially desirable)
• _________ Influence
• Participants dont respond __________ because
  someone is watching them

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Sources of Error in Research

• Demand____________
• Aspects of the study that allow participants to
  _________ _____ purpose influences them to
  respond in certain way
• Participants want researcher to ______ _____
• ___________ Effect
• Roethlisberger Dickson (1939) study on effects
  of lighting in electrical plant
• Treatment group changes behavior because they
  _______ they are receiving treatment/special
  attention

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Solutions to Error involving Participants

• Assess a response participants cant _______
  (i.e. physiological response)
• Dont allow participants to know you are ________
  them
• Use ______ study
• Treat all groups involved in study as ________ as
  possible

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Reliability

• ___________, _________, stability
• True score Measured score _________ error
• Reliable measure has _____ measurement error
• Reliability coefficient ranges from ________

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3 Types of Reliability

• Test-______
• Measure _____ participant with same assessment
  tool ___ different times
• __________ scores Scores should be similar
• EXCEPT WHEN??
• When measuring _______ constructs like
• Fatigue
• Hunger

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3 Types of Reliability

• ______-half
• Divide assessment into ___ equal parts (i.e.,
  odds vs. evens) ________ scores from both halves
• Used when test-retest isnt _________

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3 Types of Reliability

• Inter-______
• Degree of __________ between 2 or more
  ___________ who are recording same data
• If observational study does not report
  inter-rater reliability, what does this mean?
• Most likely only _____ observer involved

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Validity vs. Reliability

• Validity
• _________
• Reliability
• ____________, consistency
• If I have a reliability study, is it guaranteed
  to be valid??
• _____ - you can have a ____________ _________
  assessment

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3 Types of Construct Validity

• Convergent
• Demonstrated by a strong relationship between
  scores obtained from two __________ methods of
  measuring the ______ construct
• Example
• When several measures of intelligence come up
  with the same results
• _________ ________ Technique
• Take groups known to _________ on a
  characteristic see if they differ on a measure
  of the characteristic

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3 Types of Construct Validity

• Divergent
• Demonstrating that a measure of one construct
  does _____ correlate strongly with measures of
  ___________ constructs
• Example
• Showing that an assessment of intelligence does
  NOT correlate with an assessment of altruism

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3 Types of Construct Validity

• Content
• Demonstrating that the measure represents ____
  aspects of the construct
• Example
• Does the GRE Psychology exam represent all
  aspects of the field of Psychology?