problem-4.1
problem-4.1
The tables can be made using table(). Different tables are
produced for each level of the last variable specified. For
example, to answer the first question we have:
> attach(samhda)
> table(amt.smoke, marijuana, gender)
, , gender = 1
marijuana
amt.smoke 1 2 9
1 13 3 0
2 3 0 0
3 5 0 0
4 5 1 0
5 2 5 0
6 11 13 0
7 25 38 1
98 6 148 0
99 4 4 2
...
> detach(samhda)
By looking at the help page for samhda to see how the
variables are coded, we can see that a marijuana value of
2 is "not smoking", and an amt.smoke value of 7 is "no
smoking in the last 30 days," whereas 1 indicates "smoking every
day." The table for males (gender equal 1) shows that in
this data set marijuana smokers are much more likely to be among
the heavier cigarette smokers.