lines = 'iq_change group_number
3  1
2  1
6  1
10 1
10 1
5  1
10 2
4  2
11 2
14 2
3  2
20 3
9  3
18 3
19 3'
con = textConnection( lines )
DF = read.table( con, header=TRUE )
close(con)