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Questions and Answers
What type of validity ensures that a test reflects the full range of content covered in a subject area?
What type of validity ensures that a test reflects the full range of content covered in a subject area?
Which type of reliability involves measuring the same test at two different points in time to assess consistency?
Which type of reliability involves measuring the same test at two different points in time to assess consistency?
What is the main focus of criterion validity in testing?
What is the main focus of criterion validity in testing?
Which method of establishing reliability assesses the variations of scores within a single test over different trials?
Which method of establishing reliability assesses the variations of scores within a single test over different trials?
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Which of the following describes halo effect in rating errors?
Which of the following describes halo effect in rating errors?
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Which measurement represents the theoretical distance from the mean in a standardized way?
Which measurement represents the theoretical distance from the mean in a standardized way?
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What does the Coefficient Alpha measure in terms of internal consistency?
What does the Coefficient Alpha measure in terms of internal consistency?
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Which error occurs when a rater is influenced by their recent observations rather than overall performance?
Which error occurs when a rater is influenced by their recent observations rather than overall performance?
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What does a correlation coefficient (r) of -0.7 indicate about the relationship between two variables?
What does a correlation coefficient (r) of -0.7 indicate about the relationship between two variables?
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Which regression method is specifically used to predict binary outcomes?
Which regression method is specifically used to predict binary outcomes?
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What is the purpose of factor analysis in research?
What is the purpose of factor analysis in research?
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What does the term 'residuals' refer to in the context of regression analysis?
What does the term 'residuals' refer to in the context of regression analysis?
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In multiple regression, what does the equation $Y = a + b_1X_1 + b_2X_2 + ... + b_iX_i$ represent?
In multiple regression, what does the equation $Y = a + b_1X_1 + b_2X_2 + ... + b_iX_i$ represent?
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What is meant by 'shrinkage' in the context of multiple regression?
What is meant by 'shrinkage' in the context of multiple regression?
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What distinguishes a moderator variable from a mediator variable?
What distinguishes a moderator variable from a mediator variable?
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Which method is NOT typically used for selecting predictors in multiple regression?
Which method is NOT typically used for selecting predictors in multiple regression?
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Study Notes
Validity
- Definition: A test or instrument's ability to measure what it's intended to measure.
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Types:
- Logical Validity (Face Validity): Appears valid based on its definition.
- Content Validity: Covers the entire scope of the topic being measured.
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Criterion Validity:
- Concurrent Validity: Aligns with a known criterion at the same time.
- Predictive Validity: Predicts future outcomes accurately.
- Construct Validity: Measures a specific theoretical construct.
Reliability
- Definition: Consistency and stability of measurement scores over time.
- Equation: Observed Score = True Score + Error Score
- Sources of Measurement Error: Test procedures, instrumentation, scoring, and participant influences.
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Types:
- Interclass Reliability: Simple correlation, but limited.
- Intraclass Reliability: Uses repeated measures ANOVA, accounting for variations.
- Intertester Reliability (Objectivity): Agreement between different raters.
Establishing Reliability
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Methods:
- Test-Retest: Checks stability over time.
- Alternate Forms: Consistency across different versions of the same test.
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Internal Consistency: Consistency within the test itself:
- Same-day Test-Retest: Repeated testing on the same day.
- Split-Half Technique: Divides a test and compares scores.
- Coefficient Alpha (Cronbach’s Alpha): Measures internal consistency.
Other Measurement Issues
- Standard Error of Measurement: Estimates error in an observed score.
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Standard Scores:
- Z-scores: Indicates how many standard deviations a score is away from the mean.
- T-scale: Transforms scores to a scale with a fixed mean and standard deviation.
Rating Scales and Errors
- Types of Rating Scales: Numerical, checklist, forced choice, rankings.
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Common Rating Errors:
- Leniency: Overly generous ratings.
- Central Tendency: Avoiding extreme ratings.
- Halo Effect: One trait influences ratings of other traits.
- Proximity Errors: Rating based on recent performance.
- Observer Bias & Expectation: Preconceived expectations affect ratings.
Correlation and Prediction
- Understanding Correlation: Examines relationships between variables, indicating how they change together.
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Correlation Coefficient (r):
- Range: -1.0 to +1.0
- Positive Correlation: 0 to +1.0 (variables increase together)
- Negative Correlation: -1.0 to 0 (one variable increases as the other decreases)
- Significance of r: Sample size and alpha level affect significance.
Regression and Prediction
- Regression Equations: Predict one variable from another.
- Line of Best Fit: Minimizes discrepancies between predicted and actual values.
- Standard Error of the Estimate: Measures the accuracy of predictions.
Types of Correlation Analysis
- Partial Correlation: Removes the effect of a third variable on two others.
- Semi-Partial Correlation: Removes the effect of a third variable on only one variable.
Multiple Regression
- Definition: Predicts a criterion variable using multiple predictor variables.
- Logistic Regression: Predicts binary outcomes (yes/no).
- Discriminant Function Analysis (DFA): Predicts group membership when there are multiple groups.
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Methods for Selecting Predictors:
- Maximum R²: Selects predictors that maximize the variance explained.
- Stepwise: Enters and removes variables based on their contribution.
- Forward Selection: Adds predictors one at a time.
- Backward Selection: Removes predictors one at a time.
- Hierarchical: Adds predictors based on theoretical knowledge.
Moderators and Mediators
- Moderator: A third variable that influences the strength or direction of the relationship between two other variables.
- Mediator: A third variable that explains the relationship between two other variables.
Advanced Correlation: Canonical Correlation and Factor Analysis
- Canonical Correlation: Examines relationships between sets of predictor and criterion variables.
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Factor Analysis: Reduces a set of variables to underlying factors (constructs).
- Steps: Develop a model, assess intercorrelations, determine factors, and analyze factor loadings.
- Eigenvalue: The variance explained by a factor.
- Factor Loadings: Correlations between each variable and a factor.
- Rotation Methods: Transform factor loadings for easier interpretation.
Conclusion
Validity and reliability are essential components of measurement, ensuring that research findings are meaningful and trustworthy. Understanding these concepts aids in designing robust studies and interpreting results accurately.
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Description
Test your understanding of the key concepts of validity and reliability in psychometrics. This quiz covers definitions, types, and measurement errors. Perfect for psychology students looking to deepen their knowledge.
