The arithmetic mean and standard deviation of a certain normal distribution are 15.5 and 1.5, respectively. What value is exactly 2 standard deviations less than the mean?  Choose the most appropriate option.
A) 10.5  B) 11  C) 11.5  D) 12  E) 12.5
The value which isexactlytwo SD less than the mean is:mean-2*SD=15.5-2*1.5=12.5.   Answer: 12.5.
<result>E</result>
The arithmetic mean and standard deviation of a certain normal distribution are 15.5 and 1.5, respectively. What value is exactly 2 standard deviations less than the mean?