GMAC never wants us to actually calculate the freaking SDs but wants us to understand the logic behind it.
SD is nothing but finding the average of a set and substracting each members of the set from this AV and squaring them. Then you can sum them up and divide the number of NUMBERS in the set.
Since the average is 6,
adding 6,6 will not affect the top of the equation because (6-6)^2 =0
So we will not anything to the top of the equation but divide it 102 instead of 100!
So the SD will be a smaller number.
And it also makes sense because adding more numbers that are close to the average will make the DEVIATION less.
if add 1000000000000000000000 of 6 to this equation SD will get close to the 0...
REMEMBER SD
>0
So if you know this concept and come across this question , it will take you 3 seconds to solve it. NOT 4!
LGTCH
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