Thread: SD!

guys take a look at this question:

If A has 25 items with average of 100. B has 30 items of which 25 of it has same average as A. the remaining 5 is equal to 100.
thus
B = A, 100,100,100,100,100

will they have same SD or not?

my response is they will have different SD. pls any prove why am wrong here.

thanks

Hey lawochekel.

Without more information, you can't conclude whether the standard deviations (or standard errors) are the same or not.

what other information needed to decide whether the SD is the same or not?

You need either the underlying distribution, a sample (of which you estimate the standard error) or the actual value itself.