What are the two types of test items discussed in the lecture?
- Dichotomous items
- Polytomous items
Dichotomous items have two scores, while polytomous items have more than two scores.
A dichotomous item has how many item scores?
Two
Example: multiple-choice items with correct and incorrect answers.
What is an example of a polytomous item?
Likert item
Example: Responses ranging from 1 (strongly agree) to 5 (strongly disagree).
The central aim of item analysis is to obtain insight into what?
Quality of the items and the test
This includes defining the purpose of the test and investigating the psychometric quality of the items.
What does the p-value represent in the context of dichotomous items?
Item difficulty (popularity)
It is the mean item score for dichotomous items.
What is the a-value in item analysis?
Proportion of persons choosing an incorrect item option
It can be used to investigate the quality of alternative answers.
True or false: The p-value in item analysis is the same as the p-value in hypothesis testing.
FALSE
The p-value in item analysis refers to item difficulty, not statistical hypothesis testing.
What is item discrimination?
An item’s ability to differentiate between groups of persons
It is not related to racial, ethnic, or gender discrimination.
What are the two indexes of discrimination mentioned?
- Disc index
- Item-test correlation
These indexes help assess how well an item differentiates between test-takers.
How is the Disc index calculated?
Difference between proportion correct in high and low scoring groups
This helps to evaluate the effectiveness of an item.
What is the corrected item-total correlation?
Correlation between score on a specific item and the sum of the other items without that item
It provides a more accurate picture of an item’s relationship to the total score.
What does a high item-test correlation indicate?
High discrimination and a good item
It suggests that the item is effective in distinguishing between different levels of test-takers.
What is the purpose of the score matrix in item analysis?
To analyze item scores of individuals
It helps in calculating p-values and a-values for items.
In the context of item analysis, what does a mean score indicate?
Average performance on an item
It is used to assess item difficulty and effectiveness.
What is the significance of item-total correlations?
They indicate how well an item correlates with the total test score
This helps in evaluating the quality of each item.
What is the item-total correlation for dichotomous item scores?
Point biserial correlation
This correlation indicates the relationship between an individual item score and the total score.
Which statement is true regarding the item scores of 8 persons on a test of 3 items?
(d) none of the above statements is correct
The options provided do not accurately reflect the data given.
What are the item selection criteria for tests?
- Number of items
- p-values
- Shape of distribution
- Discrimination
- Content considerations
These criteria help ensure the reliability and validity of the test.
True or false: An easy test best discriminates between persons with low total scores.
TRUE
This is because easy tests yield higher p-values, indicating more correct responses from low-scoring individuals.
What is the definition of reliability in classical test theory?
The extent to which test scores are similar if a test is administered multiple times to the same person under the same conditions
Reliability focuses on the consistency of test scores across different administrations.
What are the components of a test score according to classical test theory?
- Systematic part
- Random part
The systematic part reflects consistent factors, while the random part includes temporary influences.
What does the formula O = T +/- E represent?
Observed score = true score +/- error
This formula illustrates the relationship between observed scores, true scores, and measurement error.
What are the methods for estimating reliability?
- Parallel method
- Test-retest method
- Split-half method
- Coefficient alpha
These methods provide different approaches to assess the reliability of test scores.
What is the parallel method for estimating reliability?
Construct two similar tests and compute the correlation between test scores
This method requires careful construction of parallel tests.
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Week 121
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Week 232
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Week 336
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Week 415
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Week 4 part 215
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Week 536
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Week 625
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Week 710
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Summary The World of Psychological Testing11
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Summary Test Norms19
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Summary Reliability17
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Summary Test Development, Item Analysis, and Fairness14
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Summary Validity25
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Summary Factor Analysis13
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Summary Intelligence: Theories and Issues19
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Summary Individual Intelligence Tests13
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Summary Objective Personality Tests13
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Summary Clinical Instruments and Methods21
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Summary Projective Techniques11
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Summary Interests and Attitudes14
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Chapter 1528
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Chapter 1414
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Chapter 1330
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Chapter 1226
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Chapter 828
