http://hk.knowledge.yahoo.com/question/?qid=7007103000447
有人計左個variance出黎
甘covariance點計呀?可唔可以用返o個個例子示範計一次?
唔該晒
更新1:
大致上都明點計法 不過請問點解E(X) = 3, E(Y) = 2 o既?(係咪求其代一pair數入去就得架la?) 同埋個E字有咩意思架? 唔該晒!