Question

suppose x can take the four values of 1, 2, 3, 4 with probabilities .5, .1, .2, .2 respectively. work out the mean u and the variance sigma^2 of X

Answer 1

\[\mu=.5(1)+.1(2)+.2(3)+.2(4)\]
\[\sigma^2=.5(1-\mu)^2+.1(1-\mu)^2+.2(1-\mu)^2+.2(1-\mu)^2\]