probability variance formula

If X is a discrete random variable then variance of X denoted by V(X) is defined as V(X) = E [X - E(X)] 2 V(X) = E(X 2 ) - [E(X)] 2 ..

We have = n(n-1) p 2 (p+q) n - 2 + np = n 2 p 2 - np 2 + np = n 2 p 2 + np(1-p) = n 2 p 2 + npq Now V(x) = E(x 2 ) - [E(x)] 2 = n 2 p 2 + npq - n 2 p 2 = n..

Let X be a discrete random variable which can assume values x 1 , x 2 , x 3 ,x n with probabilities p 1 , p 2 , p 3 .. p n respectively then (a) Mean of X or expectation of X denoted by E(X) or m is given by (b) Variance of X denoted by s 2 is given ..

Calculate the standard deviation and the variance for the following data 7, 8, 11, 6, 13, 8, ..

Calculate the variance and standard deviation from the following data..

Standard Deviation of a statistical data is defined as the positive square root of the arithmetic mean of the squared deviations of items from their arithmetic mean of the series under consideration. The standard deviation is denoted by s (sigma). The standard deviation is als..

of a statistical data is defined as the positive square root of the arithmetic mean of the squared deviations of items from their arithmetic mean of the series under consideration. The standard deviation is denoted by s (sigma). The standard deviation is also known as Root Mean Square Deviatio..

1. If x is a discrete random variable assuming the values x 1 , x 2 , x 3 ,.,x n with probabilities p 1 , p 2 , p 3 ,., p n respectively then (x 1 ,p 1 ), (x 2 , p 2 ),(x n , p n ) defines a probability distribution of X. 2. Let n independent bernoulli trials be pe..

The variance of the Poisson distribution = l = 2 Recurrence relation is given by ..

. For an individual series, For a frequency distribution, Variance = (S.D.) 2 Coefficient of variation (C.V) Let s 1 and s 2 be the S.D of the two groups containing n 1 and n 2 items respectively. Let a..