The format is:
List of 5
$ vdose : num [1:5] 0 1.56 3.12 6.25 12.5
$ vdose2 : num [1:5] 0 2.44 9.77 39.06 156.25
$ fdose : Factor w/ 5 levels "0","1.5625","3.125",..: 1 2 3 4 5
$ twofdose : Factor w/ 2 levels "0","1": 1 1 2 2 1
$ number.young:List of 5
..$ : num [1:32] 0 0 0 0 0 0 0 0 0 0 ...
..$ : num [1:36] 0 0 0 0 0 0 0 0 0 0 ...
..$ : num [1:45] 0 0 0 0 0 0 0 0 0 0 ...
..$ : num [1:37] 0 0 0 0 0 0 0 0 0 0 ...
..$ : num [1:17] 0 0 1 0 0 0 0 3 0 0 ...