Calculate the mean, median, and mode for the following four distributions (a–d):

a b c d 2 1 1 2 2 2 3 3 4 3 3 4 5 4 3 5 8 4 5 6 a b c d 9 5 5 6 10 5 8 6 11 5 8 7 11 6 8 8 11 6 9 8 8 10 9 11