Dunnett analysis error $ operator is invalid for atomic vectors

Here is my real data. Group A is my reference and I want to compare the other groups to group A (dunnett analysis). I want to simulate another 5 random numbers for Group A based on the mean and std for my current Group A. and use the combined the data to do the analysis.
Group Y
A 30.17
B 30.65
A 30.35
C 30.57
D 30.75
A 30.52
E 30.05
F 30.56
G 30.86
A 30.89
H 30.69
I 31.19
J 30.68
K 30.84
A 30.82
B 24.13
C 24.5
D 24.28

Here is my R code:

import the real data

data <- read_excel("Path/Sample.xlsx")


do 100 times Simulations


create vectors to save the anona results.

res = vector("list",sim)

Create data frames for the simulated the data

df_sim<- replicate(n=sim,data.frame(Group = rep('A',5), Y=rep(0,5)),simplify=FALSE)

create data frames for the combined data( real data merged with simulated data)


for (i in 1:sim)


df_merge[[i]]$Group<-as.factor( df_merge[[i]]$Group)

res[[i]]<- lm(df_merge[[i]]$Y ~ df_merge[[i]]$Group, data = df_merge[[i]])

#Dunnect analysis comparing other groups to group A

got error df_merge[[i]]Group : operator is invalid for atomic vectors



The code works well until I do the Dunnnet analysis using the emmeans function. I got the error df_merge[[i]]Group : operator is invalid for atomic vectors.

If I change my code to lssquare[[i]]=emmeans(res[[i]],specs=trt.vs.ctrlk~getElement(df_merge[[i]],"Group"),data=df_merge[[i]])

i got the error:Error in [.data.frame(tbl, , vars, drop = FALSE) :
undefined columns selected

Any ideas on how to fix this error? Appreciated for anly help

Try with:

lm(Y ~ Group, data = df_merge[[i]])
1 Like

Thanks Alexis,it works! Appreciated!

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