I tried to draw a point on all boxplots for their means, I did:

boxplot( Daten$weight~interaction(Daten$Dosis,Daten$sex, drop=TRUE))
means<-tapply( Daten$weight, Daten$Dosis, mean)
points(means, pch=5, col="red", lwd=5)

but only the boxplots for male got that point on them, its really weird
because I don't think that I separated the sex in the codes above

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