将一个三阶多项式及其方程添加到r中的一个ggplot中 [英] Adding a 3rd order polynomial and its equation to a ggplot in r
问题描述
我绘制了以下数据并添加了一个更平滑的黄土。我想添加一个三阶多项式及其方程(包括残差)到图中。任何建议?
set.seed(1410)
dsmall< -diamonds [sample(nrow(diamonds),100 ),]
df <-data.frame(x= dsmall $ carat,y= dsmall $ price)
p <-ggplot(df,aes(x,y ))
p < - p + geom_point(alpha = 2/10,shape = 21,fill =blue,color =black,size = 5)
#黄土更平滑
p< - p + geom_smooth(method =loess,se = TRUE)
我怎么能添加一个三阶多项式?我试过:
p < - p + geom_smooth(method =lm,se = TRUE,fill = NA, = lm(y〜poly(x,3,raw = TRUE)),color =red)
最后,我该如何将三阶多项式方程和残差添加到图中?
我试过了:
pre $ lt; code> lm_eqn = function(df){
m = lm(y〜poly x,3,df))#3次多项式
eq < - 替代(italic(y)== a + b%。%italic(x)*,〜italic(r)^ 2〜 =〜r2,
列表(a =格式(coef(m)[1],digits = 2),
b =格式(coef(m)[2],digits = 2),
r2 = format(summary(m)$ r.squared,digits = 3)))
as.character(as.expression(eq))
}
data.label< - data.frame(x = 1.5,y = 10000,label = c(lm_eqn(df)))
p < - p + geom_text (data = data.label,aes(x = x,y = y,label = label),size = 8,family =Times,face =italic,parse = TRUE)
$ c第1部分:拟合一个多项式,使用参数:$ b $
-
method = lm
- 您做得正确
formula = y〜poly(x,3,raw = TRUE)
- 即不要在调用lm
代码:
p + stat_smooth(method =lm,se = TRUE,fill = NA,
formula = y〜poly(x,3,raw = TRUE),color =red )
第二部分:添加方程式:
- 修改您的函数
lm_eqn()
以正确指定数据源为lm
- 您在错误位置有一个右括号
- 使用
annotate()
来定位标签,代码:
lm_eqn = function(df){
m = lm(y〜poly(x,3),df)#3次多项式
eq < - 替代(italic(y)== a + b%。%italic(x)*,~~ italic(r)^ 2〜=〜r2,
list(a = format (m)[2],digits = 2),
r2 = format(summary(m)$ r.squar ed),digits = 3)))
as.character(as.expression(eq))
}
p + annotate(text,x = 0.5 ,y = 15000,label = lm_eqn(df),hjust = 0,size = 8,
family =Times,face =italic,parse = TRUE)
I have plotted the following data and added a loess smoother. I would like to add a 3rd order polynomial and its equation (incl. the residual) to the plot. Any advice?
set.seed(1410) dsmall<-diamonds[sample(nrow(diamonds), 100), ] df<-data.frame("x"=dsmall$carat, "y"=dsmall$price) p <-ggplot(df, aes(x, y)) p <- p + geom_point(alpha=2/10, shape=21, fill="blue", colour="black", size=5) #Add a loess smoother p<- p + geom_smooth(method="loess",se=TRUE)
How can I add a 3rd order polynomial? I have tried:
p<- p + geom_smooth(method="lm", se=TRUE, fill=NA,formula=lm(y ~ poly(x, 3, raw=TRUE)),colour="red")
Finally how can I add the 3rd order polynomial equation and the residual to the graph? I have tried:
lm_eqn = function(df){ m=lm(y ~ poly(x, 3, df))#3rd degree polynomial eq <- substitute(italic(y) == a + b %.% italic(x)*","~~italic(r)^2~"="~r2, list(a = format(coef(m)[1], digits = 2), b = format(coef(m)[2], digits = 2), r2 = format(summary(m)$r.squared, digits = 3))) as.character(as.expression(eq)) } data.label <- data.frame(x = 1.5,y = 10000,label = c(lm_eqn(df))) p<- p + geom_text(data=data.label,aes(x = x, y = y,label =label), size=8,family="Times",face="italic",parse = TRUE)
解决方案Part 1: to fit a polynomial, use the arguments:
method=lm
- you did this correctlyformula=y ~ poly(x, 3, raw=TRUE)
- i.e. don't wrap this in a call tolm
The code:
p + stat_smooth(method="lm", se=TRUE, fill=NA, formula=y ~ poly(x, 3, raw=TRUE),colour="red")
Part 2: To add the equation:
- Modify your function
lm_eqn()
to correctly specify the data source tolm
- you had a closing parentheses in the wrong place - Use
annotate()
to position the label, rather thangeom_text
The code:
lm_eqn = function(df){ m=lm(y ~ poly(x, 3), df)#3rd degree polynomial eq <- substitute(italic(y) == a + b %.% italic(x)*","~~italic(r)^2~"="~r2, list(a = format(coef(m)[1], digits = 2), b = format(coef(m)[2], digits = 2), r2 = format(summary(m)$r.squared, digits = 3))) as.character(as.expression(eq)) } p + annotate("text", x=0.5, y=15000, label=lm_eqn(df), hjust=0, size=8, family="Times", face="italic", parse=TRUE)
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