Hello! I tried to change it before ggplot, but it shows a similar message......
mydata$Weight = as.numeric(mydata$Weight)
library(ggplot2)
ggplot(mydata,aes(x=Temperature,y=Weight))+geom_bar(stat="identity", data =mydata,fill = NA, color = "black")+
geom_jitter( position = position_jitter(0.2),
color = "black") +
geom_errorbar(
aes(ymin = Weight-sd, ymax = Weight+sd),
data = mydata, width = 0.2)