The arithmetic mean and standard deviation of a certain normal distribution are 12 and 1.2, respectively. What value is exactly 2 standard deviations less than the mean?
Choose one.
A) 9.6
B) 11
C) 11.5
D) 12
E) 12.5
Mean = 12   Two standard deviations is 1.2 + 1.2= 
<gadget id="calculator">1.2 + 1.2</gadget>
<output>2.4</output>
2.4   There could be two calues for this.   Mean + two standard deviations= 14.4   Mean - Two standard deviations = 9.6   9.6nswer choice has 9.6 and so 9.6 is the answer.
<result>A</result>
The arithmetic mean and standard deviation of a certain normal distribution are 12 and 1.2, respectively. What value is exactly 2 standard deviations less than the mean?