在 R 中的卡方 QQ 图中绘制 qqline

Question

我复制下面的代码r help。但是，qqline 函数不起作用。这是什么原因？

library(mgcViz)
y <- rchisq(500, df = 3)
## Q-Q plot for Chi^2 data against true theoretical distribution:
qqplot(qchisq(ppoints(500), df = 3), y, main = expression("Q-Q plot for" ~~ {chi^2}[nu == 3]))
qqline(y, distribution = function(p) qchisq(p, df = 3), prob = c(0.1, 0.6), col = 2)

谢谢！

Answer 1

要添加带有 mgcViz 的 qqline，您需要使用 ggplot:

library(mgcViz)
y <- rchisq(500, df = 3)
## Q-Q plot for Chi^2 data against true theoretical distribution:
qqplot(qchisq(ppoints(500), df = 3), y, main = expression("Q-Q plot for" ~~ {chi^2}[nu == 3]))

# Add qq line
library(ggplot2)
ggplot2::last_plot() + qqline(y, distribution = function(p) qchisq(p, df = 3), prob = c(0.1, 0.6), col = 2)

要查看您的 qqline 的截距和斜率，您可以执行以下操作：

my.qqline = qqline(y, distribution = function(p) qchisq(p, df = 3), prob = c(0.1, 0.6), col = 2)
> my.qqline$data
   intercept     slope
1 0.08606285 0.9290453

在 R 中的卡方 QQ 图中绘制 qqline

Drawing qqline in the Chi- Square QQ plot in R

plot

r

quantile