Question: New Standard Deviation

Comment on New Standard Deviation

hulk1906 - January 10, 2019
Quick and easy way to solve this questions is to use 1 for the 10 values; Average is 1 and the std is 0. add K and you see the std is still 0.
gmat-admin's picture

gmat-admin - January 11, 2019

That's a great strategy. However, we need to recognize that this approach allows us to eliminate C, D and E.
The answer can still be either A or B, because if d = 0, then 10d = 0

Cheers,
Brent

sjiang24 - November 5, 2021
See I don't use complex numbers

we can suppose every number here is 1 so the mean is 1, SD 1-1 is 0

you add 1 into every number the mean is 2, 2-2 is still 0
gmat-admin's picture

gmat-admin - November 6, 2021

That works!

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