处理R错误：rep（value [[k]]，length.out = n）：尝试复制类型为'closure'的对象

Question

我正在尝试针对正态分布绘制卡方。我收到以下错误，但不确定为什么： “在rep（value [[k]]，length.out = n）中：尝试复制'closure'类型的对象”

library(tidyverse)
set.seed(10204)

mu = 0
sd = 1
norm_df <- tibble(X = seq(1, 10, 1), 
                  Z = dnorm(x = X, mu, sd))
chi_df <- tibble(Xseq = seq(1, 10, 1), 
                 X = dchisq(x = Xseq, df = 1))

ggplot(data = norm_df, aes(x = X)) + 
  geom_histogram(y = stat(density), binwidth = 1) + 
  geom_line(data = chi_df, aes(x = Xseq - 0.5, y = X))

我希望能够绘制出一个图，卡方是分布上的线，法线的频率计数是直方图。