统计正态分布问题
统计正态分布问题
A financial analyst states that the price of X of a long term government bond one year later is normally distributed with a mean of µ=$1000 and standard deviation of sigma(?)=$72.
a) what is the 93rd percentile of the long term government bond's price?
b)what is the median of the long term government bond's price?
c)what is the minimum value of the price of long term government bond(X) where 75% of the prices exceed that value?
d) what is the minimum value of the price of long term government bond(X) where 25% of the prices exceed that value?
a) > qnorm(0.93,1000,72)
[1] 1106.257
The 93rd percentile of the long term government bond's price is $1106.257
b) Normal distribution is symmetry.Therefor,the median is same with mean,namely $1000.
c) > qnorm(0.25,1000,72)
[1] 951.4367
d)> qnorm(0.75,1000,72)
[1] 1048.563怎么算的？