If a variable be such that np observations are all equal to 1 and the remaining nq observations are all equal to 0. (p + q = 1). Find the mean and standard deviation of that variable.

If a variable be such that np observations are all equal to 1 and the remaining nq observations are all equal to 0 (p + q = 1), then find the mean and standard deviation of that variable.

The mean and standard deviation of observations are 8 and 14 respectively. If each observation be multiplied by 3, the find the new and mean and new standard deviation of the resulting observation.

The mean and standard deviation of six 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

The mean and standard deviation of a group of 100 observations were found to be 20 and 3, respectively. Later on it was found that three observations were incorrect, which were recorded as 21, 21 and 18. Find the mean and standard deviation if the incorrect observations are omitted.

A discreate random variable x has the following probability distribution: Find mean and standard deviation.

A variable x takes only two values x_1 , x_2 with equal frequencies. Find the mean deviation about mean and the standard deviation.

If all the values of a variable are equal to 7 then what is its variance.

In a series of 2n observations, half of them equal a end remaining half equal -a. If the S.D. of the observationsis 2, then |a| equals (1) 1/n (2) sqrt2 (3) 2 (4) sqrt2/n

The mean of 5 observations is 4.4 and the variance is 8.24. If three of the five observations are 1,2 and 6, find the other two.

If overlinex is the mean of a set of n observations x_1 , x_2 , x_3…..,x_n then sum_(i=1)^n(x_i-overlinex) is equal to