如何在R中的ggplot2中繪制2x2x2設計的回歸線？

Question

我有如下數據（dtf.long）：

nutrition fertilizer season seedlingdensity plandensity fitted
  nitrogen  none       wet        5             19       6
  nitrogen  none       dry        5             19       8
  nitrogen  phos       wet        4             23       16
  nitrogen  phos       dry        5             19       10
  iron      none       wet        5             29       21
  iron      none       dry        5             19       14
  iron      phos       wet        4             23       12
  iron      phos       dry        5             20       14
  ....
  ...

總共有16個重復。 我想繪制一個回歸圖，y軸上的對數（seedlingdensity）和x軸上的log（plandensity）都由食物組成。 兩種肥料的顏色和季節可以不同。

我試圖寫出代碼，但我仍然不知道該如何為季節編碼

來自回歸的模型擬合存儲在擬合列中

summary_dat = dtf.long %>%
              group_by(nutrition, fertilizer, season) %>%
              summarise(mean_predict=mean(fitted),
                        sd_predict = sd(fitted),
                        n_predict = n()) %>%

  mutate(se_predict = sd_predict / sqrt(n_predict),
         lower_ci = mean_predict - qt(1 - (0.05 / 2), n_predict - 1) * se_predict,
         upper_ci = mean_predict + qt(1 - (0.05 / 2), n_predict - 1) * se_predict)

ggplot() + 
  geom_point(data=dtf.long, aes(x=log(plantdensity), y=log(seedlingdensity), group=fertilizer, color = fertilizer), position=position_dodge(width=0.5)) + 
  geom_errorbar(data=summary_dat, aes(x=log(plantdensity), ymax=upper_ci, ymin=lower_ci, group=fertilizer, color=fertilizer), position=position_dodge(width=0.5), width=0.2) + 
  geom_point(data=summary_dat, aes(log(plantdensity), y=mean_predict, group=fertilizer, color=fertilizer), size=3, position=position_dodge(width=0.5)) + 
  facet_grid(nutrition ~ .) + xlab("log(Plant Density") + ylab("log(Seedling Density)")

Answer 1

您可以將參數shape添加到對geom_point的調用中，並將其映射到geom_point可變season的值。

ggplot() + 
 geom_point(data=dtf.long, 
    aes(x=log(plantdensity), 
        y=log(seedlingdensity), 
        group=fertilizer, 
        color = fertilizer,
        shape = season), 
    position=position_dodge(width=0.5)) + 
 geom_errorbar(data=summary_dat, 
    aes(x=log(plantdensity), 
        ymax=upper_ci, 
        ymin=lower_ci), 
    position=position_dodge(width=0.5), width=0.2) + 
 facet_grid(nutrition ~ .) + 
 xlab("log(Plant Density") + 
 ylab("log(Seedling Density)")

您可以在ggplot網站的此頁面上找到更多示例