What are the similarities and differences between these data sets in terms of their centers and their variability? data set a: 21, 26, 29, 33, 40, 43 data set b: 20, 23, 28, 30, 44, 47 select from the drop-down menus to correctly complete the statements. comparing the centers of the data sets, the median for data set a is the median for data set b. the mean for data set a is the mean for data set b.