问题描述
SQLEXPRESS01
我想将library(ggplot2)
library(fitdistrplus)
set.seed(1)
dat <- data.frame(n = rlnorm(1000))
# binwidth
bw = 0.2
# fit a lognormal distribution
fit_params <- fitdistr(dat$n,"lognormal")
ggplot(dat,aes(n)) +
geom_histogram(aes(y = ..density..),binwidth = bw,colour = "black") +
stat_function(fun = dlnorm,size = 1,color = 'gray',args = list(mean = fit_params$estimate[1],sd = fit_params$estimate[2]))
# my defined function
myfun <- function(x,a,b) 1/(sqrt(2*pi*b(x-1)))*exp(-0.5*((log(x-a)/b)^2)) # a and b are meanlog and sdlog resp.
定义的修改后的对数正态拟合为密度直方图。如何添加此功能?
解决方法
也许您正在寻找这个。由于您的myfun
的域,某些值无法显示:
library(ggplot2)
library(fitdistrplus)
set.seed(1)
dat <- data.frame(n = rlnorm(1000))
# binwidth
bw = 0.2
# fit a lognormal distribution
fit_params <- fitdistr(dat$n,"lognormal")
# my defined function
myfun <- function(x,a,b) 1/(sqrt(2*pi*b*(x-1)))*exp(-0.5*((log(x-a)/b)^2))
# a and b are meanlog and sdlog resp.
#Plot
ggplot(dat,aes(n)) +
geom_histogram(aes(y = ..density..),binwidth = bw,colour = "black") +
stat_function(fun = myfun,size = 1,color = 'gray',args = list(a = fit_params$estimate[1],b = fit_params$estimate[2]))
输出: