data fw13p10; title  'Chapter 13, exercise 10, performing tasks';
input  CLASS    TASK    TIME ;
cards;
1        1     43.2
1        2     45.8
1        3     45.4
1        4     44.7
2        1     48.3
2        2     48.7
2        3     46.9
2        4     48.8
3        1     56.6
3        2     56.1
3        3     55.3
3        4     54.6
4        1     72.0
4        2     74.1
4        3     89.5
4        4     82.7
5        1     88.0
5        2     88.6
5        3     91.5
5        4     88.2