如何绘制置信区间以更好地展示ggplot2的置信区间？

Question

This code draws the regression line, the confidence interval and the prediction interval. The confidence interval is colored in gray. I need to add a code to draw the confidence bounds to better demonstrate the confidence interval.

library(ggplot2)
x<-Allele<- c(4,4,5,5,5,7,9,11,11,11,13,14,15,15,16,17,17,19,19,19)
y<-SR<- c(5.5,5.6,5.7,6,6.1,8,8,12,12.1,13,14,14,16,16.5,17,17,
17.1,18,19,20)
D3S = data.frame(Allele, SR)
Mod <- lm(SR ~ Allele) 
pred.int <- predict(Mod, interval = "prediction")
mydata <- cbind(D3S, pred.int)
# Regression line + confidence interval
p <- ggplot(mydata, aes(Allele, SR)) +
geom_point(size=3) +
stat_smooth(method = lm, color="black")
# Add prediction intervals
myplot= p + geom_line(aes(y = lwr), color = "black", 
linetype = "dashed", size=0.8)+
geom_line(aes(y = upr), color = "black", 
linetype = "dashed", size=0.8)
myplot + theme_bw() + theme(panel.border = element_blank(), 
panel.grid.major = element_blank(),
panel.grid.minor = element_blank(), 
axis.line = element_line(colour = "black"))

Answer 1

You almost had it in your original code. Repeat the prediction with interval = "confidence" and add those lines to your plot.

# Right after you get the prediction intervals:
conf.int <- predict(Mod, interval = "confidence")

# Change the cbind line to this:
mydata <- data.frame(D3S, pred.int, conf.int) # checks names and adds .1 to dupes

# Right after you added prediction interval, do this:
myplot <- myplot + 
  geom_line(aes(y = lwr.1), color="red") + 
  geom_line(aes(y = upr.1), color="red")

Now produce your final plot as you did before.