The arithmetic mean and standard deviation of a certain normal distribution are 10.5 and 1, respectively. What value is exactly 2 standard deviations less than the mean?
Choose the correct choice from the following answers
A) 6	B) 8.5	C) 11.5	D) 12	E) 12.5
Mean = 10.5   Two standard deviations is 1 + 1= 
<gadget id="calculator">1 + 1</gadget>
<output>2</output>
2   There could be two calues for this.   Mean + two standard deviations= 12.5   Mean - Two standard deviations = 8.5   Answer choice has 8.5 and so 8.5 is the answer.
<result>B</result>
The arithmetic mean and standard deviation of a certain normal distribution are 10.5 and 1, respectively. What value is exactly 2 standard deviations less than the mean?