数码复合机怎么使用:有关概率的英文题

来源:百度文库 编辑:神马品牌网 时间:2024/04/28 21:00:05
A population consists of three numbers 5, 8, 11. Consider all possible samples size two which can be drawn with replacement from population. Find (a) the mean of the population, (b) the standard deviation of the population
(a)_________(b)__________

(a)8(b)2.45

a. 我有点忘了population mean的公式了。好像是(5+8+11)/(3+1)=6
SD更忘了。。。。