A simple of 25 variates has mean 40 and standard deviation 5 and a second sample of 35 variates has mean 45 and the standard deviation 2. Find the mean and standard deviation of the two samples of variates , taken together.

A sample of 25 variates has mean 40 and standand deviation 5 and a second sample of 35 variates has mean 45 and the standard deviation 2. Find the mean and standard deviation of the two samples of variates, taken together.

A sample of 35 observations has mean 80 men and standard deviation 4. A second sample of 65 observations has mean 70 and standard deviation =3. Find the combined mean and standard deviation.

Out of total sample survey of 100 nuts, in a first sample survey of 35 items has mean 80 and standard deviation 4. A second sample survey of 65 items has mean 70 and standard deviation 3. Find the mean and variance of combined 100 sample nuts.

Find out standard deviation and coefficient of variation .

If the first sample A of 100 items has the mean 15 and standard deviation 3 and second sample B has 150 items. If the combined mean and standard deviation of itmes of both the sample is 15.6 and sqrt(13.44) then then standard deviation of items of sample B is