Here is my data:

Here is my code and I can't seem to find what's wrong.

library(lattice)

xyplot(ChangeBPM ~ Gender, data=Data, group=Cigaretts.smoked, type=c("p","a"), auto.key=TRUE)

aggregate(ChangeBPM ~ Cigaretts.smokedGender, data=Data, mean)Gender, data=Data))

summary(aov(ChangeBPM ~ Cigaretts.smoked

Here is my error message:

xyplot(ChangeBPM ~ Gender, data=Data, group=Cigaretts.smoked, type=c("p","a"), auto.key=TRUE)

Error in eval(substitute(groups), data, environment(x)) :

object 'Cigaretts.smoked' not found

Is the headings in cigarettes smoked wrong? is it a "." ? or is it the group part

Thanks