Scores of students in a large class have a distribution that is symmetric about the mean 60. 68 percent of the distribution lies within one standard deviation 10 of the mean, and 95 percent of the distribution lies within two standard deviations of the mean. What percent of the distribution is between score of 70 and score of 80?
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A27%
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B26%
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C14%
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D13.5%
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E13%
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正确答案: D