data management数学题
researchers have observed that regular smokers have an average lifespan that is normally distributed and is 68 years with a standard deviation of 10 years .what percent of smokers will live beyond age 76?
人气：417 ℃ 时间：2020-06-27 10:22:54
解答
此题本意是有正态分布曲线N(68,10),要求计算P（X>=76)
u=(X-μ)/σ =(76-68)/10 = 0.8,查标准正态分布表可得Φ(0.8)=0.7881
P（X>=76）=(1-Φ(u))/2=(1-0.7881)/2=0.106
即能够超过76岁的概率是10.6%
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