The mean (or average) of a data set is calculated by summing all the values and then dividing by the number of values. In this case, we also need to consider the frequency of each value.

From the table, we have the following data set: 8 (2 times), 10 (1 time), 12 (4 times), 16 (3 times), 18 (3 times), 20 (1 time), 24 (6 times).

So, the sum of all values is: 2*8 + 1*10 + 4*12 + 3*16 + 3*18 + 1*20 + 6*24 = 16 + 10 + 48 + 48 + 54 + 20 + 144 = 340

The total number of values is: 2 + 1 + 4 + 3 + 3 + 1 + 6 = 20

Therefore, the mean is: 340 / 20 = 17