Statistics - PS

rupamroy wrote:If the positive numbers d is the standard deviation of n,k and p then the standard deviation of n+1, k+1 and p+1 is

a) d+3
b) d+1
c) 6d
d) 3d
e) d

It's important to note that standard deviation is a measurement of the variation (or dispersion) of a set of numbers.
So, adding 1 to every number in a set will have no effect on the variation of those numbers. As such, the standard deviation of n+1, k+1 and p+1 will still be d.

Answer = E

Example
The set {1,2,3,4} has a certain standard deviation. Adding 13 to every number in the set gives us {14,15,16,17}, and we can see that the standard deviation of this new set will be the same as the standard deviation of the old set (since the dispersion for each set is identical).

Cheers,
Brent