Find the following probability

Question

For the following probability distributions:

   x     0    1    2

P(x)  0.5  0.4  0.1

 

a. Find E(x)

b. Find σ(x)

Answer 1

The sum E(X) = Σx_kp_k is known as the mathematical expectation of X (or the expected value, or the mean µ).

E(X) = 0(0.5) + 1(0.4) + 2(0.1) = .4 + .2 = 0.6

TO CALCULATE SIGMA where σ² is Var(X):

VAR(X)  is computed by taking the sum of terms each of which is a probability times (X-μ)² -- using the table--

and after you have computed that, take its square root to get σ