Psychological Testing Principle Types of Psychological Tests o

Psychological Testing

Principle Types of Psychological Tests o Mental ability tests Intelligence – general n Aptitude – specific n o Personality n scales Measure motives, interests, values, and attitudes

Key Concepts in Psychological Testing o Standardization Test norms n Standardization group n o Reliability n Correlation coefficient o Validity Content validity n Criterion-related validity n Construct validity n

Classical Test Theory o Goal of testing is to identify subject’s “true score” on a given attribute. Classical Test Theory says… Test Score = True Score + Error of Measurement Goal of test developers is to minimize this!

Sources of Measurement Error o Where do these measurement errors come from? n Item sampling error n Internal consistency error n Time sampling error n Random error

Testing o How do psychologists know how well their test is measuring a person’s true score? n By assessing test reliability Assesses Time sampling error Test-Retest reliability Alternate or Parallel Form reliability Internal Consistency reliability Assesses Internal consistency error Assesses Item sampling error

Test-Retest Reliability

Judging Internal Consistency Correlation Matrix Q 9 Q 10 Q 17 Q 18 Scale Q 9 Q 10 Q 17 Q 18 I I Scale Mean if Item Deleted Q 9 Q 10 Q 17 Q 18 1. 0000. 1829. 1888. 1730 1. 0000. 5718. 4031 1. 0000. 5302 1. 0000 Corrected Variance if Item Deleted Item. Total Correlation Anxiety Scale Items am carefree 8. 9250 8. 4753. 2220 am rarely 9. 4750 overcome 9. with worries 6. 2272. 5460 I am carefree am not a 9. 2875 worrier 5. 3720. 6160 10. I am rarely overcome with rarely feel fearful or anxious 9. 1750 6. 8804. 5141 . 0494. 3452. 4367 worries. 2999 17. I am not a worrier 18. I rarely feel fearful or anxious Reliability Coefficients Alpha = Squared Multiple Correlation . 6846 4 items Standardized item alpha = . 6749 Alpha if Item Deleted. 7513. 5655. 5080. 5930

Testing o How do psychologists know their test is measuring what they think it is measuring? n By assessing test validity o o o Content validity Criterion-related validity Construct validity

Fig. 9 -4, p. 339

Fig. 9 -5, p. 340

Assessing Construct Validity Convergent Construct. Validity Divergent Construct Our measure of extraversion should not be correlated with things unrelated to extraversion

Assessing Construct Validity Convergent Construct. Validity Divergent Construct Correlations Our measure of impatience HEIGHT should be not. Impatience correlated be correlated with Scale ‘ 02 with SHOEto impatience. Impatience ‘ 03 things related unrelated to. Scale impatience. HEIGHT ‘ 02 SHOE EXTRA 202 ‘ 03 1. 000. 857** -. 085. 275*. 857**. 275*1. 000. 039 1. 000 Impatience Scale -. 085 level (2 -tailed). . 039 1. 000 *. Correlation is significant at the 0. 05 **. Correlation is significant at the 0. 01 level (2 -tailed).

Testing o Utility of Psychological Tests n Reliability o o o n Alternate or Parallel Form Internal Consistency Test-Retest Validity o o o Content Criterion-Related Construct