value labes Stata vs factors

Dear Sir/Madam,
I converted my Stata Rgenmetvl.dta file with read.dta succesfully in R's
Rgenmetvl.Rdata. However, factors give problem in certain calculations,
e.g.:

mean(Rgenmetvl$sex)

[1] NA
Warning message:
In mean.default(Rgenmetvl$sex) :
  argument is not numeric or logical: returning NA

What can I do?

Factors can't be averaged. You can average a score based on a factor 
though, as in

mean(c(1,2)[Rgenmetvl$sex])

or

mean(as.numeric(Rgenmetvl$sex))

These do the same thing, but the former allows you more control of the 
scores asssigned. Notice that the values need to be in the order of 
levels(Rgenmetvl$sex).

Alternatively, use read.dta(...., convert.factors=FALSE) to get a 
version of data containing the original numeric values.

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