A stem-and-leaf plot for the numbers of touchdowns scored by all 120 NCAA Division I Football Bowl Subdivision teams is shown. Find the probability that a team chosen at random scored
(a) At least 51 touchdowns,
(b) Between 20 and 30 touchdowns, inclusive,
(c) More than 72 touchdowns. Are any of these events unusual? Explain.

Key: 19 19 2 4 5 6 6 77 7 7 8 8 8 99 3 001 1 1 2 2 2 333 3 4 4 5 5 6 6 68 8 89 9 99 4 01 1 1 1 2 2 3 33 4 4 5 5 6 6 6 7 77 7 8 89 999999 5 00 0 0 00 2 2 3 4 4 5 6 67 7 8 8 8 9 6 0 1 1 2 2 2 2 3 4 4 5 5 5 5 6 67 8 89 7 1 1 2 36 8 8 4 9