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By definition, what percent of IQ scores falls between -2SD and +2SD?

a. 97.5
b. 80
c. 68
d. 95

User Shinil
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1 Answer

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Final answer:

Approximately 95% of IQ scores fall between -2 standard deviations and +2 standard deviations from the mean, according to the empirical rule.

Step-by-step explanation:

By definition, approximately 95% of IQ scores fall between -2 standard deviations and +2 standard deviations from the mean in a normal distribution. This is based on the empirical rule, also known as the 68-95-99.7 rule, which states that about 68% of values lie within 1 standard deviation of the mean, about 95% within 2 standard deviations, and about 99.7% within 3 standard deviations.

When considering IQ scores, which are normally distributed with a mean of 100 and a standard deviation of 15, a score between -2SD and +2SD would be between 70 (100 - 2*15) and 130 (100 + 2*15). Thus, option d. 95 is the correct answer.

User SethML
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