Help, I want to do a T-test with two groups, but can't make the groups.

[stijn1]

The problem I'm facing is that I have the results of a survey with answers reaching from 1 to 5. How do I give 3 =< the value 1 and < 3 the value 0. Any help would be greatly appreciated!

[FJCC]

Here is an example with some data I invented.

DF <- data.frame(Score = c(3,2,4,4,1,2,1,5,4,3,2,4))
DF$Binary <- as.numeric(DF$Score >= 3)
DF
   Score Binary
1      3      1
2      2      0
3      4      1
4      4      1
5      1      0
6      2      0
7      1      0
8      5      1
9      4      1
10     3      1
11     2      0
12     4      1