Find the mean, median, mode and range of the data set after you perform the given operation on each data value.
13, 17, 15, 18, 21, 13, 20; add 3.7
a) mean 20.4, median 20.7, mode 16.7, range 8
b) mean 16.7, median 20.7, mode 18.7, range 8
c) mean 21.7, median 14.7, mode 16.7, range 8
d) mean 16.7, median 21.7, mode 16.7, range 8