A variable, W, is normally distributed with a mean of 12. 68% of its observations lie between 8 and 16. The coefficient of variation of W is ________.
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A. B. C. D.Explanation
For a normal distribution, 68% of the observations lie within one standard deviation of the mean. Hence, the standard deviation of X equals 12-8 = 4. The coefficient of variation is then equal to standard deviation/mean = 4/12 = 0.33.