A group of 10 observations has mean `5 and 2sqrt6`. another group of 20 observationshas mean `5 and S.D. 3sqrt2`, then the S.D. ofcombined group of 30 observations is

Out of 250 observations, the first 100 observations have mean 5 and the average of the remaining 150 observations is 25/3 What is the average of the whole group of observations ?

The mean of a set of 20 observations is 8 and of another set of 30 observations is 10. The mean of combined set is

A sample of 35 observations has the means 80 and SD. As 4. A second sample of 65 observations from the same population has mean 70 and S.D.3. The S.D. of the combined sample is -

The mean of a set of 20 observations is 8 an another set of 30 observations is 10. The mean of combined set 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 mean of 20 observations is 30. If the mean of first 15 observations is 32, find the mean of last 5 observations.

The mean of 20 observations is 30. If the mean of first 15 observations is 32, find the mean of last 5 observations.

The mean and S.D.of 1,2,3,4,5,6 is