Given the data sets below, which statements are true? select each correct answer. data set a: 50, 55, 59, 60, 60, 62, 63, 69, 72, 73, 73, 76, 77, 78, 80, 84, 86, 90 data set b: 51, 54, 56, 60, 64, 66, 67, 67, 74, 81, 84, 86, 86, 91, 92, 95, 98, 99 choose all that apply: data set a has a greater median than data set b. data set a has a smaller mean than data set b. data set a has a greater mean than data set b. data set a shows more variability than data set b. data set a shows less variability than data set b.