For a group of 100 observations, the arithmetic mean and standard deviation are 8 and `sqrt(10.5) ` respectively. The mean and standard deviation of 50 items selected from these 100 observations are 10 and 2 respectively. Then the standard deviation of the remaining 50 observation is

For a group containing 100 observations, the arithmetic mean and standard deviation are 8 and sqrt(10.5) . For 50 observations selected from the 100 observations, the arithmetic mean and standard deviations are 10 and 2 respectively. Find the arithmetic mean and the standard deviation of the other half.

If mean of squares of deviations of a set of n observations about - 2 and 2 are 18 and 10 respectively,then standard deviation of this set of observations is

If the men and standards deviation of 100 observations are 50 and 4 respectively. Find the sum of all the observations and the sum of their squares.

Suppose that mean and standard deviation of 6 observations are 8 and 4 respectively . Let each observation be multiplied by 3 Find the standard deviation of the resulting observations.

The mean and standrad deviation of 100 items are 50, 5 and that of 150 items are 40, 6 respectively. What is the combined standard deviation of all 250 items?

(b)The mean and standard deviation of 6 observations are 8 and 4 respectively.If each observation is multiplied by 3,find the new mean and new standard deviation of the resulting observations.

Mean and standard deviation of 100 items are 50 and 4 respectively. The sum of all squares of the items is