Two sample of size 100 and 150 respectively have means 50 and 60 deviation of the combined sample of size 250.

Two sample of size 100 and 150 respectively have means 15 and 16 and standard deviations 3 and 4 respectively. Find the combined mean and standard deviation of Size 250.

The means of two samples of sizes 10 and 20 respectively are 24 and 45 and the standard deviations are 6 and 11. Obtain the standard deviation of the sample of size 30 obtained by combining the two samples. (sqrt19067=138)

The means of two samples of size 40 and 50 were found to be 54 and 63 respectively. Their standard deviations were 6 and 9 respectively. The variance of the combined sample of size 90 is

Two sample of sizes 50 and 100 given. The mean of these samples respectively are 56 and 50. Then the mean of size 150 combining is

Two samples of sizes 60 and 90 have 52 and 48 as the respective A.Ms. and 9 and 12 as the respective S.Ds. Find the A.M and S.D. of the combined sample of size 150.