R工作室分層抽樣

Question

我必須計算按分類變量分層的連續變量的平均值。
我想通過結果計算年齡的平均值

我把結果變成了分類變量

#make outcome variable continuous into categorical
rhc2$Outcome<-cut(rhc2$t3d30, c(0,29,30))

summary(rhc2$Outcome)

我有 4631 個關於年齡和結果的觀察值

View(rhc2$Outcome)   
summary(rhc2$Outcome)   
 (0,29] (29,30]     
   1333    3298 

age
70.25098
78.17896
75.33197
86.07794
54.96799
43.63898
18.04199
48.42398
34.44199
68.34796

Answer 1

因為你沒有發布任何示例數據，這是你的第一篇文章，所以我冒昧地創建了虛假數據來解決你的問題。

library(tidyverse)

set.seed(41)
# since you did not provide data I made up Age
Age <- sample(seq(from = 0, to = 100, by = 1),
                    size =  4631,replace = TRUE)

# and I made up the Outcome variable
Outcome <- sample(seq(from = 0, to = 1, by = 1),
                   size = 4631,
                   replace = TRUE,
                   prob = c(0.3, 0.7))

# Create the data frame
df <- data.frame(Age,Outcome)

然后你可以使用 dplyr 包的組 function 然后是總結 function

# First group the data frame by the Outcome variable
# Then calculate the mean for every outcome variable

df %>% group_by(Outcome) %>% summarize(Mean = mean(Age))

結果：

# A tibble: 2 x 2
  Outcome  Mean
    <dbl> <dbl>
1       0  48.9
2       1  49.6