如何在R中绘制lmer回归模型的估计值？

我有如下数据：

height <- c(1,2,3,4,2,4,6,8)
weight <- c(12,13,14,15,22,23,24,25)
type <- c("Wheat","Wheat","Wheat","Wheat","Rice","Rice","Rice","Rice")
set <- c(1,1,1,1,2,2,2,2)
dat <- data.frame(set,type,height,weight)

ggplot(dat,aes(x = weight, y = height)) +
geom_point() + geom_smooth(method="lm", fill=NA) + facet_grid(~ type, scales = "free") 

ggplot(dat,aes(y = height)) +
    geom_point(aes(x = weight)) +
    geom_line(aes(x = pred)) + 
    facet_grid(~ type, scales = "free")

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然而，我注意到predict函数只有一个奇异输出。如何绘制该图以实现与上述相同的效果？或者我必须存储两个不同的预测响应，然后将其插入ggplot的x，y？

我可以调整您的绘图以显示原始值与预测值，如下所示：

height <- c(1,2,3,4,2,4,6,8)
weight <- c(12,13,14,15,22,23,24,25)
type <- c("Wheat","Wheat","Wheat","Wheat","Rice","Rice","Rice","Rice")
set <- c(1,1,1,1,2,2,2,2)
dat <- data.frame(set,type,height,weight)

ggplot(dat,aes(x = weight, y = height)) +
geom_point() + geom_smooth(method="lm", fill=NA) + facet_grid(~ type, scales = "free") 

ggplot(dat,aes(y = height)) +
    geom_point(aes(x = weight)) +
    geom_line(aes(x = pred)) + 
    facet_grid(~ type, scales = "free")

在示例图中，虽然您在x轴上有

权重

，但模型中的结果变量令人困惑。通常情况下，y轴上会有结果/预测变量，因此我会绘制模型预测，如下所示：

ggplot(dat,aes(x = height)) +
    geom_point(aes(y = weight)) +
    geom_line(aes(y = pred)) + 
    facet_grid(~ type, scales = "free")