作业帮matlab怎么求对数正态分布函数的分位数（反函数）么
来源：学生作业帮 编辑：作业帮 分类：综合作业 时间：2024/05/15 16:35:26
matlab怎么求对数正态分布函数的分位数（反函数）么
如题,最好有代码,今天刚刚知道matlab可以求分位数,
如题,最好有代码,今天刚刚知道matlab可以求分位数,
logninv Inverse of the lognormal cumulative distribution function (cdf).
X = logninv(P,MU,SIGMA) returns values at P of the inverse lognormal
cdf with distribution parameters MU and SIGMA.MU and SIGMA are the
mean and standard deviation,respectively,of the associated normal
distribution.The size of X is the common size of the input arguments.
A scalar input functions as a constant matrix of the same size as the
other inputs.
Default values for MU and SIGMA are 0 and 1,respectively.
[X,XLO,XUP] = logninv(P,MU,SIGMA,PCOV,ALPHA) returns confidence bounds
for X when the input parameters MU and SIGMA are estimates.PCOV is a
2-by-2 matrix containing the covariance matrix of the estimated parameters.
ALPHA has a default value of 0.05,and specifies 100*(1-ALPHA)% confidence
bounds.XLO and XUP are arrays of the same size as X containing the lower
and upper confidence bounds.
比如期望0,标准差1的对数正态分布,求1%分位数
输入
logninv(0.01,0,1)
即可
再问： 可是我现在不知道函数当中的那两个参数，怎么办
再答： 你是知道分布求分位数还是求一组样本的分位数？前者怎么可能不知道期望和方差？后者用函数prctile
再问： 一语惊醒门外人，哈哈，重新整理一下思路和方法再试试，谢谢啊。不懂的话可不可以再问您，能不能留个qq或者邮箱？
X = logninv(P,MU,SIGMA) returns values at P of the inverse lognormal
cdf with distribution parameters MU and SIGMA.MU and SIGMA are the
mean and standard deviation,respectively,of the associated normal
distribution.The size of X is the common size of the input arguments.
A scalar input functions as a constant matrix of the same size as the
other inputs.
Default values for MU and SIGMA are 0 and 1,respectively.
[X,XLO,XUP] = logninv(P,MU,SIGMA,PCOV,ALPHA) returns confidence bounds
for X when the input parameters MU and SIGMA are estimates.PCOV is a
2-by-2 matrix containing the covariance matrix of the estimated parameters.
ALPHA has a default value of 0.05,and specifies 100*(1-ALPHA)% confidence
bounds.XLO and XUP are arrays of the same size as X containing the lower
and upper confidence bounds.
比如期望0,标准差1的对数正态分布,求1%分位数
输入
logninv(0.01,0,1)
即可
再问： 可是我现在不知道函数当中的那两个参数，怎么办
再答： 你是知道分布求分位数还是求一组样本的分位数？前者怎么可能不知道期望和方差？后者用函数prctile
再问： 一语惊醒门外人，哈哈，重新整理一下思路和方法再试试，谢谢啊。不懂的话可不可以再问您，能不能留个qq或者邮箱？