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[英]Compute mean and standard deviation by group for multiple variables in a data.frame
[英]Getting mean and standard deviation from groups in a data.frame
我具有列表形式的心率數據,其中四個類別1AS,1CS,1AI,1CI各自具有可變大小。 我想為列表中的每個類別輸出均值和標准差。 我有這種格式的數據來計算ANOVA和Tukey,我已經成功完成了,但是平均值讓我很困惑!
Group HR
1 1AS 300
2 1AS 280
3 1AS 260
4 1AS 250
5 1AS 300
6 1AS 272
7 1AS 250
8 1AS 198
9 1AS 200
10 1AS 195
11 1AS 214
12 1AS 249
13 1AS 240
14 1CS 250
15 1CS 236
16 1CS 200
17 1CS 272
18 1CS 206
19 1CS 203
20 1CS 237
21 1CS 214
22 1AI 218
23 1AI 276
24 1AI 240
25 1AI 264
26 1AI 300
27 1AI 315
28 1AI 300
29 1AI 285
30 1AI 286
31 1CI 167
32 1CI 233
33 1CI 214
34 1CI 219
35 1CI 214
36 1CI 246
37 1CI 230
38 1CI 218
假設您的數據在一個名為DF
的data.frame中:
by(DF$HR,DF$Group,mean)
# DF$Group: 1AI
# [1] 276
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1AS
# [1] 246.7692
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1CI
# [1] 217.625
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1CS
# [1] 227.25
by(DF$HR,DF$Group,sd)
# DF$Group: 1AI
# [1] 30.93946
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1AS
# [1] 36.48551
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1CI
# [1] 23.25595
# -------------------------------------------------------------------------------------------------------------------------------------------------------------
# DF$Group: 1CS
# [1] 25.77236
使用ave
另一種解決方案:
ave(DF$HR, DF$Group)
給出均值和
ave(DF$HR, DF$Group, FUN=sd)
DF是您的數據框。
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