The circle graph shows the results of a survey of a college class. Find the mean, median, and mode of the data. (If necessary, round your answers to two decimal places.)
I can't figure out the mean.
median = 20 yr
mode = 19 yr
mean = (19x9 + 20x6 + 21x7 + 22x3 + 23x2+ 24x1 + 28x2 + 36x1 + 68x1 + 18x4)/(9+6+7+3+2+1+2+1+1+4)
mean = 403/18 ~22.39