√100以上 p(x y) independent 102041-P(x y) independent
The events X and Y are said to be independent if the probability of X is not affected by the occurrence of Y That is, X, Y independent if and only if P(XY)=P(ot Y) Here P(XY) means theBut using the de nition of conditional probability we nd that P(Y = jX= ) = P(Y = \X= ) P(X= ) = P(Y = ) or P(Y = \X= ) = P(X= )P(Y = ) This formula is symmetric in Xand Y and so if Y is independent of Xthen Xis alsoIn real life, we usually need to deal with more than one random variable For example, if you study physical characteristics of people in a certain area, you might pick a person at random and then look at his/her weight, height, etc Http Web Eecs Umich Edu Fessler Course 401 E 94 Fin Pdf P(x y) independent