datamanagement数学题researchershaveobservedthatregularsmokershaveanaveragelifespanthatisnormallydistributedandis68yearswithastandarddeviationof10years.whatpercentofsmokerswilllivebeyondage76?

问题：datamanagement数学题researchershaveobservedthatregularsmokershaveanaveragelifespanthatisnormallydistributedandis68yearswithastandarddeviationof10years.whatpercentofsmokerswilllivebeyondage76?

答案：↓↓↓

邓华锋的回答：

网友采纳　　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%