The arithmetic mean of set X is zero. If Y = {-2.22; -1.96; -1.68; 1.62; 1.94; 2.16} is the subset of X consisting of all those elements in X which are more than two but less than three standard deviations away from the arithmetic mean of X, what could be equal to the standard deviation of X?	Pick: A) 0.54 B) 0.77 C) 0.82 D) 0.97 E) 1.62
This is a fairly straightforward question that can be solved quickly by just applying the options   We are provided with Mean, m= 0   and Y = {-2.22; -1.96; -1.68; 1.62; 1.94; 2.16} is the subset of S   Y consists of all those elements in X that are more than 2 but less than 3 XDs away from the arithmetic mean of X   If an element is 1 XD away from the mean, we can write it as either m + XD or m - XD   Similarly, if an element is 2 XDs away from the mean, we can write it as either m + 2*XD or m - 2*XD   So, if these elements lie within 2 and 3 XDs of mean, m=0   we can find which one of these values of XD satisfies each value within Y   Only XD = 0.77 does   Answer : 0.77
<result>B</result>
The arithmetic mean of set X is zero. If Y = {-2.22; -1.96; -1.68; 1.62; 1.94; 2.16} is the subset of X consisting of all those elements in X which are more than two but less than three standard deviations away from the arithmetic mean of X, what could be equal to the standard deviation of X?