Students of a certain course tell that the teacher has the habit of being late. The following data represents the minutes that have arrived sooner or later in a sample of 25 classes. The positive numbers represent the delays and the negative ones the early arrivals.

16 20 -40 4 55

12 -5 -7 10 12

12 15 15 15 -34

0 0 -5 -5 -5

50 2 3 5 0