Ex:The probability of a spinner landing on red is 0.3, For 12 spins, find the probability:
A. There are no more than 2 reds;
B. There are at least 5 reds.
解析:首先我們先判定這是否滿足二項式分布,fixed number of trial=12, two possible outcomes,which is land on red/ not red, fixed probability of success=0.3, the trials are independent of each other. 四項都滿足,就可以通過查表求的。
Let X be the number of red in spins.