A normal distribution of data has a mean of 15 and a standard deviation of 4. How many standard deviations from the mean is 25?

Subtract the mean from 25: 25 − 15 = 10. Divide that difference by the standard deviation, 4, to get 10 ÷ 4 = 2.5, so 25 is 2.5 standard deviations above the mean; the correct choice is 2.5.

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