9.88,10.19,11.15,11.70,12.01,12.46,13.22,13.29,14.00,14.38,14.50,14.50,15.14,15.16,15.16,15.16,15.54,15.96,16.20,16.22,16.44,17.58,20.38,21.15 is the data set, how do I find the quartiles?