2.4 A department-store chain randomly sampled 10 stores in a state. After a review of sales records, it was found that, compared with the same period last year, the following percentage increases in dollar sales had been achieved over the Christmas period this year:

10.2 3.1 5.9 7.0 3.7 2.9 6.8 7.3 8.2 4.3

a. Calculate the mean percentage increase in dollar sales.

b. Calculate the median.