Find the highest Standard deviation? a)7,-7,7,-7,7,-7 b) 7,7,7,7,7,7 c)-7,-7,-7,-7,-7,-7 d) -7,7,-7,7,-7,7?

plz provide me the steps for this... bit confused with this...

Find the highest Standard deviation? a)7,-7,7,-7,7,-7 b) 7,7,7,7,7,7 c)-7,-7,-7,-7,-7,-7 d) -7,7,-7,7,-7,7?
Standard deviation = sqrt( 1/N * sum ( x(i) - mean(x) ) ^2 )





a) 7


b) 0


c) 0


d) 7





The answer is a %26amp; d
Reply:d
Reply:The standard deviations of those 4 choices are as follows:





a) 7.6681


b) 0


c) 0


d) 7.6681





this was obtained using the equation for the estimated standard deviation:





std = sqrt( (1/(N-1)) * sum( (xi-xm)^2 )





where xi is one of the numbers from the sample, xm is the mean value of the entire sample, and N is the total number of samples
Reply:It's either a or d, but I'm not sure. I wasn't very good with Stats.