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IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. Using the empirical rule, determine the interval that would represent the middle 99. 7% of IQ scores

User Giampaolo
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17 votes
17 votes

Answer:

The interval that would represent the middle 99.7% of IQ scores is (55, 145).

Explanation:

The empirical rule tells us that 68% of values are within one standard deviation from the mean, 95% of values are within two standard deviations from the mean, and 99.7% of values are within three standard deviations from the mean.

If we want to determine the interval representing the middle 99.7% of IQ scores, we need to determine the values that are three standard deviations from the mean.

We are given the standard deviation of 15 and a mean of 100. Three standard deviations from the mean can be calculated as such:

  • 100 - 15(3) < 100 < 100 + 15(3)
  • 100 - 45 < 100 < 100 + 45
  • 55 < 100 < 145

The interval that represents the middle 99.7% of IQ scores is (55, 145).

User Gino Mempin
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