The IQ scores on the Wechsler Adult Intelligence Scale (WAIS) follow a normal distribution with a mean of 100 and a standard deviation of 15. Using standardized values, determine the IQ scores that make up the middle 70% of IQ scores. Group of answer choices: a) Between 84 and 116 b) Between 65 and 135 c) Between 55 and 85 d) Between 92 and 108
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IQ ~ N(mean = 100, SD = 15). We want the middle 70%, i.e., the central 0.70 of the distribution. Show more…
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IQ test scores. The Wechsler Adult Intelligence Scale (WAIS) is the most common test. The scale of scores is set separately for each age group and is approximately normal with a mean of 100 and a standard deviation of 15. Note: Round Z values to 2 decimal places and after all other calculations round the final answer to a tenth of a percent, e.g. .2205 becomes 22.1% and .2202 becomes 22.0%. a) (13 pts) What percent of individuals in any age group have an IQ of less than 72? b) (13 pts) What percent of individuals have an IQ above 135? c) (12 pts) What percent of individuals have an IQ between 72 and 135?
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The Wechsler Adult Intelligence Scale (WAIS) is a common IQ test for adults. The distribution of WAIS scores for persons over 16 years of age is approximately normal with mean 100 and standard deviation 15. Use the 68–95–99.7 rule to answer these questions. (a) What is the probability that a randomly chosen individual has a WAIS score of 115 or higher? (b) In what range do the scores of the middle 95% of the adult population lie?
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