AP PSYCHOLOGY

Detailed explanation-1: -Namely, 95% of the people have WAIS scores between 70 and 130. Hence, 5% of the people have WAIS scores below 70 or above 130.

Detailed explanation-2: -On the WAIS, Wechsler instead compared the scores of the test-taker to those of others in their general age group. The average score is fixed at 100, with approximately two-thirds of all scores falling somewhere between 85 and 115.

Detailed explanation-3: -For modern IQ tests, the raw score is transformed to a normal distribution with mean 100 and standard deviation 15. This results in approximately two-thirds of the population scoring between IQ 85 and IQ 115 and about 2.5 percent each above 130 and below 70.

Detailed explanation-4: -The WAIS-IV comprises a full scale IQ, as well as indexes on four factors: verbal comprehension, perceptual reasoning, working memory and processing speed.

Detailed explanation-5: -Knowing the intelligence score of one fraternal twin raised together with their sibling allows predicting the other twin’s score with an accuracy of 55%. For identical twins reared together the percentage goes up to 86%, while for identical twins reared apart the percentage drops slightly, to 76%.