I have a data set like this:
Users Age
1 2
2 7
3 10
4 3
5 8
6 20
How do I split this data set i
First, here's your dataset for my purposes: foo=data.frame(Users=1:6,Age=c(2,7,10,3,8,20))
Here's your first dataset with ages 0–5: subset(foo,Age<=5&Age>=0)
Users Age
1 1 2
4 4 3
Here's your second with ages 6–10: subset(foo,Age<=10&Age>=6)
Users Age
2 2 7
3 3 10
5 5 8
Your third (using subset(foo,Age<=15&Age>=11)) is empty – your last Age observation is over 15.
Note also that fractional ages between 5 and 6 or 10 and 11 (e.g., 5.1, 10.5) would be excluded, as this code matches your question very literally. If you'd want someone with an age less than 6 to go in the first group, just amend that code to subset(foo,Age<6&Age>=0). If you'd prefer a hypothetical person with Age=5.1 in the second group, that group's code would be subset(foo,Age<=10&Age>5).