If mean of squares of deviations of a set of `n` observations about `-2a n d2` are 18 and 10 respectively then standard deviation of this set of observations is 3 (b) 2 (c) 1 (d) None of these

Find the mean deviation from the mean for the set of obervations 1,2,3.

If the sum of the squares of deviations for 10 observations taken from their means is 2.5, then write the value of standard deviation.

The sum of deviations of n observations about 25 is 25 and sum of deviations of the same n observations about 35 is -25 . The mean of observations is

The mean deviation from the mean for the set of observation -1, 0, 4 is

In a series of 2n observations, half of them equals to a and remaining half equals to -a. If the standard deviation of the observations is 2, then find |a|.

The standard deviation of a, a+d, a + 2d,….a + 2nd is

The mean of a set of observations is a . If each observation is multiplied by b and each product is decreased by c , then the mean of new set of observations is

The mean square deviation of a set of observation x_(1), x_(2)……x_(n) about a point m is defined as (1)/(n)Sigma_(i=1)^(n)(x_(i)-m)^(2) . If the mean square deviation about -1 and 1 of a set of observation are 7 and 3 respectively. The standard deviation of those 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.

Sum of squares of deviation of 10 observations measured from 5 is 17 and sum of squares ofobservations is 170 then mean of observation is