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Mini Quiz. 1. Data that derive from the researcher's direct observation of what the subject does in some predefined context are a. L data. b. I data. c. S data. d. B data. Mini Quiz.
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Mini Quiz 1. Data that derive from the researcher's direct observation of what the subject does in some predefined context are • a. L data. • b. I data. • c. S data. • d. B data.
Mini Quiz • 2. _____________________ ask a respondent to interpret a meaningless, ambiguous stimulus in order to access the inner workings of the person's mind. • a. Rationally constructed tests • b. Projective tests • c. Factor analytic tests • d. Objective tests
Mini Quiz • 3. The basis of the _____________ method of test construction is to come up with items that seem directly, obviously, and logically related to what it is you wish to measure. • a. rational • b. empirical • c. philosophical • d. factor analytic
Mini Quiz 4. For any rationally constructed personality scale to work, it must satisfy which of the following conditions? • a. The items on the form must all be valid indicators of what the tester is trying to measure. • b. The person who completes the form must be willing to accurately report his or her self-assessment. • c. Each item must mean the same thing to the person who fills out the form as it did to the psychologist who wrote it. • d. All of the above conditions must be satisfied for the scale to work.
Mini Quiz • 5) Which one? • A) B • B) D • C) A • D) C
Basic Steps • 1) Create a test • 2) Validate the test • 3) Use the test
Positive Correlation r = 1.00
Positive Correlation . . . . . r = .64
Negative Correlation r = - 1.00
Negative Correlation . . . r = - .85 . .
Zero Correlation . . . . . r = .00
Correlation Coefficient • The sign of a correlation (+ or -) only tells you the direction of the relationship • The value of the correlation only tells you about the size of the relationship (i.e., how close the scores are to the regression line)
Which is a bigger effect? r = .40 or r = -.40 How are they different?
Practice • Do you think the following variables are positively, negatively or uncorrelated to each other? • Alcohol consumption & Driving skills • Miles of running a day & speed in a foot race • Height & GPA • Forearm length & foot length
Interpreting a Correlation • What does it actually mean in “people words”? • Binomial Effect Size Display (BESD)
BESD • 200 subjects (all sick) • Drug given to 100 of them • At the end: • 100 live and 100 die • If the effect of the drug was .00 – what does that mean?
BESD When r = .00
BESD • 200 subjects (all sick) • Drug given to 100 of them • At the end: • 100 live and 100 die • What if the drugs effect was .40 – what does that look like?
BESD When r = .40
BESD Thus, if you take the drug you have a 70% chance of living compared to only 30% if you do not take the drug! When r = .40
BESD • How to compute: • 200 subjects (all sick) • Drug given to 100 of them • At the end: • 100 live and 100 die • Drugs effect was .30
BESD When r = .30
1) Compute cell values if r = .00 BESD When r = .30
1) Compute cell values if r = .00 BESD When r = .30
1) Drop the decimal (30) 2) Divide by 2 (30 / 2 = 15) 3) Add to number in upper left cell (50 + 15 = 65) BESD When r = .30
Plug in value • Compute other cell values BESD When r = .30
Plug in value • Compute other cell values BESD When r = .30
Plug in value • Compute other cell values BESD When r = .30
BESD Practice • Create BESDs for the following • r = .10 • r = .55 • r = .80
Correlations • Small = .10 • Medium = .30 • Large = .50
Basic Steps • 1) Create a test • 2) Validate the test • 3) Use the test
Basic Steps • 1) Create a test • 2) Validate the test • 3) Use the test
Validating a Test • Is a test measuring what it is suppose to measure? • Not a YES or NO answer • Types of Validity • 1) Predictive • 2) Concurrent • 3) Content • 4) Construct
Predictive and Concurrent • Called “Criterion-orientated” validity • Does the test predict some type of criterion? • Predictive – criterion is in the future • Concurrent – criterion is in the present
Content Validity • Test items represent the entire “universe” of possible items
Group Activity • What qualities does the trait of extraversion contain? • e.g., assertiveness • Come up with at least 6 qualities • Create one item to measure each quality.
Content Validity Extraversion
Content Validity Positive Emotions Warmth Gregariousness Excitement-Seeking Assertiveness Activity Extraversion
Content Validity Have a lot of fun. Make friends easily Positive Emotions Love large parties Warmth Gregariousness Excitement-Seeking Love excitement. Assertiveness Activity Take charge. Am always busy.
Content Validity • Not normally established empirically • Established by experts in the field