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首页 > 解决方案 > 如何将 R^2 和回归值添加到 ggplot2 中的多因素设计

r - 如何将 R^2 和回归值添加到 ggplot2 中的多因素设计

问题描述

我有一个 2 x 2 的设计。我需要为每个因素添加 R2 和回归值——在图表上进行颜色编码。我使用部分使用这个答案来修改这个问题的代码，但我仍然只获得一条回归线。此外，回归方程打印不清晰。我需要四个颜色编码的回归方程。

fertilizer <- c("N","N","N","N","N","N","N","N","N","N","N","N","P","P","P","P","P","P","P","P","P","P","P","P","N","N","N","N","N","N","N","N","N","N","N","N","P","P","P","P","P","P","P","P","P","P","P","P")

    level <- c("low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","high","low","low","high","low")

    growth <- c(0,0,1,2,90,5,2,5,8,55,1,90,2,4,66,80,1,90,2,33,56,70,99,100,66,80,1,90,2,33,0,0,1,2,90,5,2,2,5,8,55,1,90,2,4,66,0,0)


    repro <- c(1,90,2,4,66,80,1,90,2,33,56,70,99,100,66,80,1,90,2,33,0,0,1,2,90,5,2,2,5,8,55,1,90,2,4,66,0,0,0,0,1,2,90,5,2,5,8,55)

    df <- data.frame(fertilizer, level, growth, repro)


    lm_eqn = function(df){
      m = lm(growth ~ repro, df);
      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));                 
    }

    eq <- ddply(df,.(fertlizer + level),lm_eqn)

ggplot(df, aes(x=growth, y=repro, color = fertilizer)) +  theme_bw() + geom_point(aes(colour = factor(fertilizer)), size = 0.1,alpha = 0.3) +
  geom_smooth(method='lm',se=FALSE, aes(colour = factor(fertilizer)), formula = y ~ x)+ scale_color_manual(values=c("#E69F00", "#1B9E77")) +
  facet_wrap(.~level, scales = "free") + theme(legend.position = "none") + theme(aspect.ratio = 1.75/1) + geom_text(data=eq,aes(x = 50, y = 25,label=V1), parse = TRUE, inherit.aes=FALSE, size = 2)

在此处输入图像描述

标签： rggplot2linear-regression

解决方案

有很多方法可以实现非重叠，这是非常基本且非常手动的。

添加一个新列eq用于映射geom_text(aes(y = y_pos))，而不是当前使用的常量。

eq$y_pos <- c(24, 36, 8, 24)

ggplot(df, aes(x=growth, y=repro, color = fertilizer)) +
  geom_smooth(method='lm',se=FALSE, aes(colour = factor(fertilizer)), formula = y ~ x) +
  geom_point(aes(colour = factor(fertilizer)), size = 0.1,alpha = 0.3) +
# change here 
  geom_text(data=eq,aes(x = 50, y = y_pos, label=V1), parse = TRUE, inherit.aes=FALSE, size = 2) +
# ----
  scale_color_manual(values=c("#E69F00", "#1B9E77")) +
  facet_wrap(.~level, scales = "free") +
  theme_bw() + 
  theme(legend.position = "none",
        aspect.ratio = 1.75/1)

也许更优雅和灵活的解决方案是提取模型的截距并将该值设置为每个方程的 y 位置。或者您可以在给定的 x 值处提取模型值并使用它。

如果有帮助的话，很高兴分享其中一个，但是有很多时间用于发布图，我会回到手动文本放置，就像这样。

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