ggplot2：高亮區域取決於dnorm函數

Question

我想突出顯示垂直線和正常分佈函數之間的區域。我知道它是如何與離散值一起工作的，但stat_function讓我感到困惑。代碼看起來像這樣：

library(ggplot2) 

n1 <- 5 

ggplot(data.frame(x = c(-2, 2)), aes(x)) + 
    stat_function(fun = dnorm, args = list(sd = 1/sqrt(n1))) + 
    geom_vline(xintercept = 0.5, linetype = "dashed", color = "red", size = 1) + 
    geom_vline(xintercept = -0.5, linetype = "dashed", color = "red", size = 1) + 
    ylim(c(0, 1.5)) + 
    theme_light() + 
    geom_rect(aes(xmin = 0.5, xmax = Inf, ymax = Inf, ymin = 0), fill = "grey", alpha = .3) 

我知道我需要將ymax更改爲x> 0.5的值。問題是如何？

編輯： 我看着這個應該和我一樣的問題。當我重寫代碼他們的方式，在突出的作品，但它並沒有給我一個合適的正態分佈了，因爲你可以在這裏看到：

library(dplyr) 

set.seed(123) 
range <- seq(from = -2, to = 2, by = .01) 
norm <- rnorm(range, sd = 1/sqrt(n1)) 
df <- data_frame(x = density(norm)$x, y = density(norm)$y) 

ggplot(data_frame(values = norm)) + 
    stat_density(aes(x = values), geom = "line") + 
    geom_vline(xintercept = 0.5, linetype = "dashed", color = "red", size = 1) + 
    geom_vline(xintercept = -0.5, linetype = "dashed", color = "red", size = 1) + 
    ylim(c(0, 1.5)) + 
    theme_light() + 
    geom_ribbon(data = filter(df, x > 0.5), 
      aes(x = x, ymax = y), ymin = 0, fill = "red", alpha = .5) 

當我堅持stat_function和使用geom_ribbon與子集爲在同一個問題中提出，它突出了越野車，你可以看到這裏：

ggplot(data_frame(x = c(-2, 2)), aes(x)) + 
    stat_function(fun = dnorm, args = list(sd = 1/sqrt(n1))) + 
    geom_vline(xintercept = 0.5, linetype = "dashed", color = "red", size = 1) + 
    geom_vline(xintercept = -0.5, linetype = "dashed", color = "red", size = 1) + 
    ylim(c(0, 1.5)) + 
    theme_light() + 
    geom_ribbon(data = filter(df, x > 0.5), 
     aes(x = x, ymax = y), ymin = 0, fill = "red", alpha = .5) 

還不滿意。

Answer 1

這裏有一個辦法：

library(ggplot2) 
n1 <- 5 
ggplot(data.frame(x = c(-2, 2)), aes(x)) + 
    stat_function(fun = dnorm, geom = "area", fill = "grey", alpha = 0.3, args = list(sd = 1/sqrt(n1)), xlim = c(-0.5,0.5)) + 
    stat_function(fun = dnorm, args = list(sd = 1/sqrt(n1))) + 
    geom_vline(xintercept = 0.5, linetype = "dashed", color = "red", size = 1) + 
    geom_vline(xintercept = -0.5, linetype = "dashed", color = "red", size = 1) + 
    ylim(c(0, 1.5)) + 
    theme_light() 

在stat_function一個可以定義不同的geom，只需選擇適合自己需要的人。