The first of the two samples have 100 items with mean 15 and S.D.3. If the whole group has 250 items with mean `15.6` and `S.D. = sqrt13.44` then S.D. of the second group is

The first of the two samples have 100 items with mean 15 and S.D.3. If the whole group has 250 items with mean 15.6 and S.D.=sqrt(13.44) then S.D. of the second group is

The first of two samples has 100 items with mean 15 and standard deviation 3. If the whole group has 250 items with mean 15.6 and standrd deviation sqrt(13.44) then standard deviation of second group is

The first of two samples has 100 times with mean 15 and standard deviations 3. If the whose group has 250 items with mean 15.6 and standard deviation sqrt(3.44) Find the standard deviation of the second group.

A group of 10 observations has mean 5 and 2sqrt(6) another group of 20 observationshas mean 5 and S.D.3sqrt(2) ,then the S.D.ofcombined group of 30 observations is