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Psychometrics

Psychometrics

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Psychometrics

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  1. Psychometrics Dr Jacqui McKechnie

  2. Psychometric Tests General Tests WAIS and WISC Specific Tests BDI and BAI Personality Tests MMPI-II Projective Tests Rorschach inkblot test

  3. Theories of Intelligence Spearman (1904) Two-Factor Theory of Intelligence. 1) a general factor - g factor 2) specific factors Guildford (1967) 120 different factors Thurstone (1938) 7 ‘primary mental abilities’ Goleman (1995) Emotional Intelligence Gardner (1983) Multiple intelligence - 6 types

  4. Crystallised Intelligence specific knowledge e.g. vocabulary increases with age depends on level of education influenced by environmental factors

  5. Fluid Intelligence basic powers of reasoning and problem solving Cattell’s IQ test starts to decline at 21 years falls steeply after 60 years influenced by genetic factors

  6. IntelligenceTests Binet & Simon (1905) - developed tests for children based on concept of mental age. • IQ not fixed • would help to direct education • should not be used as a label Stanford - Binet Scale adapted for American children by Terman & Yerkes.

  7. It was used for classification • IQ score - fixed • could rank order individuals • differences attributed to innate genetics Intelligence Quotient mental age x 100 chronological age

  8. Adults standardised to make the average result 100 This makes the average IQ 100. 95% score 68 - 132 68% score 84 - 116

  9. Types of IQ test British Ability Scalesdeveloped in 1970’s Individual tests:- WAIS - Weschler Adult Intelligence Scale WISC - Weschler Intelligence Scale for Children Verbal - vocabulary, arithmetic, reasoning Performance - picture completion, block design

  10. Group:- AH test - Alice Heim Group comparison, economical • Sample Questions • Give the next but one member of the series: • 1/2, 3/5, 5/8, 7/11 …… • Here are words denoting five generations in one family. Which has two, and only two, younger relations: • grandmother, great-grandson, son, father, grandson • Here is to there as these is to: • yonder, that, others, those, this 11/17

  11. Reliability and Validity Selection There may be biases inherent in the items chosen. Reliability It is important that if the same people are tested they give the same results. • Test-retest method • Split-half reliability • Alternate-forms reliability

  12. Validity Do tests measure what they claim to measure? Does the test result predict performance? • Predictive validity • Face validity • Content validity • Concurrent validity • Construct validity • Consensual validity

  13. Response Bias How do we make sure that the test isn’t producing a tendency to answer the questions in one way rather than another? • Questions themselves could be producing the answers. • The way a question is phrased can also produce a response. • People try to present themselves in the best light possible. • Are tests biased towards certain cultures? Social desirability response set Acquiescence response set

  14. Reliability 3 - 5yrs r = +0.5 12 - 14yrs r = +0.9 r = +0.7 66yrs Validity IQ & academic achievement r = +0.4 - 0.7 IQ & occupational status r = +0.5 - 0.6 r = +0.3 IQ & income

  15. Inheritance of Intelligence Burt (1955) 80% hereditary 20% environmental Kamin (1984) 0% hereditary 100% environmental Identical twins r = 0.87 Fraternal twins r = 0.53 Separated identical twins r = 0.66 - 0.77 Siblings r = 0.5 Foster children reared together r = 0.2

  16. Intelligence and Race IQ scores between black and white Americans have shown differences of 15 points. Jensen (1969) stressed biological differences Environmentalists: • tests were culturally biased • environment may be different • black people may experience prejudice and discrimination

  17. Scarr and Weinberg (1976) adoption study - black children had IQ 25 points higher. Tyler (1965) IQ differences between black Americans in north and south. Educational differences account for up to 24 points in IQ tests

  18. Yerkes (1921) Administered IQ tests to 125,000 young men in US army. Goddard (1913) Administered IQ test to immigrants to USA.

  19. Items Relate to the Culture of the Edwards River Community many 1. What comes next in the sequence: one, two, three, ___________ ? 2. As wallaby is to animal, so cigarette is to ________________ ? (Choose from leaf, tree, tobacco, habit, lung cancer) 3. One of the following items may not be classified with salt water crocodile. Which one? (marine turtle, frilled lizard, budgerigar, black snake) 4. Which items may be classified with sugar? (honey, witchetty grub, flour, water-lilies) 5. We eat food and __________ water. Supply the missing verb. tree black snake all of them eat