SD-Good One

[nitya34]

Which data set has the greater standard deviation, data set K or data set L ?

(1) Every element in data set K is a multiple of 3.

(2) Every element in data set L is a multiple of 9.


OA is............ E...............Thanks

[niraj_a]

not sure between C and E. i guess E.

since both sets contain numbers that are evenly spaced, the mean = median for both sets. but, if one set has more / less numbers than the other set, then the actual value of the mean, and by extension, the actual value of the SD could be different.

i sure hope i'm right.

[tohellandback]

IMO E
consider sets {3,6,9} and {9}
now consider sets {3} and {9,18,27}

[david2008]

Yup should be E

SD depends on number of items in the set as well as the mean and distribution of the numbers. Any 1 element set would have a 0 SD so by not knowing the number of numbers in each set, we can't conclude what the relative SD is,

[shibal]

E

K could be 3,3,3 or 3,6,9,12
L could be 9,9,9 or 9,18,27

[mehravikas]

Standard deviation changes when the numbers in the set are multiplied / divided by the same constant. However we dont know here how many elements are there in both the sets and the range of the set.

Therefore answer should be E.

[aj5105]

right said. (E). we need to know the number of elements in the set.