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Re: The arithmetic mean and standard deviation of a certain [#permalink]
15 Mar 2012, 07:35
The arithmetic mean and standard deviation of a certain normal distribution are 13.5 and 1.5, respectively. What value is exactly 2 standard deviations less than the mean? a) 10.5 b) 11 c) 11.5 d) 12 e) 12.5
The value which is exactly two SD less than the mean is: mean-2*SD=13.5-2*1.5=10.5.