Class 1: 80, 81, 81, 75, 70, 72, 74, 76, 77, 77, 77, 79, 84, 88, 90, 86, 80, 80, 78, 82
Class 2: 70, 90, 88, 89, 86, 86, 86, 86, 84, 82, 77, 79, 84, 84, 84, 86, 87, 88, 88, 88
Rearranging the grades in ascending order:
Class 1: 70, 72, 74, 75, 76, 77, 77, 77, 78, 79, 80, 80, 80, 81, 81, 82, 84, 86, 88, 90
Class 2: 70, 77, 79, 82, 84, 84, 84, 84, 86, 86, 86, 86, 86, 87, 88, 88, 88, 88, 89, 90
Note the following formulae:
Following the formulae written above, the complete table is drawn below
Note that:
The students that work in small groups will have their grades close to each other because they worked together. This means that their Mean Absolute Deviation will be smaller
Therefore, class 1 was the lecture and class 2 was the small group