Testing Intelligence

ARE YOU OVER-TESTED?  Your age group is the most tested group in the history of the United States.

Types of Tests  Aptitude Test - predicts your ability to learn a new skill. (future performance)  Achievement Test - reflects what you have learned. (current performance)

Wechsler Adult Intelligence Scale (WAIS)  The most widely used intelligence test created by David Wechsler.  Contains verbal and performance subtests  Look at page 446 in test to see sample questions.  If scores on verbal and performance are drastically different, it could indicate a learning disability.

Test Criteria  A PSYCHOLOGICAL TESTS SHOULD BE Standardized Standardized Reliable Reliable Valid Valid

Standardization  Standardization – defining meaningful scores by comparison with the performance of a standardized group  For a test to be standardized, the condition of taking the test need to be as similar as possible  Results should form a normal curve (bell shaped) with most scores falling in the average and less score falling in the extremes.  A score is given based on how the test-taker’s score varies from the mean.

The Normal (Bell) Curve  Standardized test results usually form a bell-shaped curve (normal curve – most scores fall near the average and few scores lie at the extremes). REFER TO PAGE 434

The Normal (Bell) Curve and Standard Deviation   The Standard Deviation (z score) for the normal curve on the WAIS and other standardized Intelligence tests is always 15. The S.D. is how much scores vary from the mean.

Normal (Bell) Curve and Standard Deviation   What this means is about 68% of the test takers will score between 15 points lower than the mean and 15 points higher than the mean because 68% is ALWAYS 1z (z=standard deviation). Q What are these scores on the WAIS?. The other 32% that take a test score outside of that.

Standard Deviation   About 95% of test takers will score between 30 pts. lower than the mean and 30 pts. higher than the mean because about 95% is ALWAYS 2z (standard deviation). Q What are these scores on the WAIS?

The Bell Curve

If the mean on a test is 80 and the standard deviation (1z score) is % of the test takers scored between a ___ and ____? 2. What percent of the test takers scored between a 70 and a 90? 3. If I scored 1 standard deviation above the mean what was my score? 4. If I scored 3 standard deviations below the mean what was my score?

If the mean on a test is 80 and the standard deviation ((1)z score) is 5  What percent of test takers scored above a 90?  If I scored a 70 what is my z score?  On the Normal curve for a standardized intelligence test (ex.- the WAIS) what percent of the population scores above an 85?  What percent scored above a 115?

NC Teacher refuses to give standardized test.  Teacher says no to testing - YouTube Teacher says no to testing - YouTube Teacher says no to testing - YouTube

Test to Measure Optimism and Pessimism in Personality  1. Prefer A. Hamburgers B. Hot Dogs  2. What kinds of grades do you tend to get? A. Good B. Bad  3. Which do you prefer? A. Talking on telephone B. Going to Movies  4. Which color do you like best? A Red B Blue

Validity  Validity – the extent to which a test measures or predicts what it is supposed to, the accuracy of the test.  Was the Optimism test valid?  Can you make it valid?  (glass, thoughts on rainy days)

Types of Validity  Content validity – How well does the test measure the entire range of material it is supposed to test? Ex. of low content validity – spending 5 minutes on depression in class and asking 30 questions on depression for the Ch. 16 test. Ex. of low content validity – spending 5 minutes on depression in class and asking 30 questions on depression for the Ch. 16 test.  Predictive validity – the success of the test in predicting the behavior it is supposed to predict. Ex. SAT is said to predict your performance in college. It actually only predicts freshman year success. High school grades much better predictor. Ex. SAT is said to predict your performance in college. It actually only predicts freshman year success. High school grades much better predictor. Criterion – the behavior a test is supposed to measure. Criterion – the behavior a test is supposed to measure.

Reliability  Reliability – the extent to which a test yields consistent results, consistency of the test.

Measuring Reliability  Equivalent –form reliability – correlation between performance on different forms of the test. Q State check for on EOC’s?  Test-retest reliability – correlation between one’s score of the first administration of the test and the score of the second administration of the test. (Ex. SAT’s)  Split-half reliability – randomly dividing the tests into two parts and correlating one’s performance on the two parts.  The closer the correlation is to +1 … the more reliable the test is Stanford-Binet and the WAIS have a reliability of +.9 Stanford-Binet and the WAIS have a reliability of +.9

Testing Mental Retardation  Those whose IQ score falls below 70 are labeled as having mental retardation. (pg. 452)  Criteria for diagnosis: Low test score Low test score Difficulty adapting to the normal demands for independent living Difficulty adapting to the normal demands for independent living  Mental retardation affects 1% of the population.  Mental retardation affects males more than females