#pnorm函数的使用形式:pnorm(p,mean=0,sd=1,lower.tail=TRUE,log.p=FALSE)
#a.P(X>=2)
pnorm(2,mean=2,sd=3,lower.tail=FALSE)
#b.P(1<=X<7)
pnorm(7,mean=2,sd=3,lower.tail=TRUE)-pnorm(1,mean=2,sd=3,lower.tail=TRUE)
#c.P(-2.5<=X<-1)
pnorm(-1,mean=2,sd=3,lower.tail=TRUE)-pnorm(-2.5,mean=2,sd=3,lower.tail=TRUE)
#d.P(-3<=X-2<3)即P(-1<=X<5)
pnorm(5,mean=2,sd=3,lower.tail=TRUE)-pnorm(-1,mean=2,sd=3,lower.tail=TRUE)
产生100个均值为0标准差为1的正态分布随机数:rnorm(100, mean = 0, sd = 1) 指数分布数 dnorm(x, mean = 5, sd = 1, log = TRUE)