The following data give the numbers of computer keyboards assembled at the Twentieth Century Electronics Company for a sample of 25 days. 45, 52, 48, 41, 56, 46, 44, 42, 48, 53, 51, 53, 51, 48, 46, 43, 52, 50, 54, 47, 44, 47, 50, 49, 52, a. Calculate the values of the three quartiles and the interquartile range. b. Determine the (approximate) value of the 53rd percentile. c. Find the percentile rank of 50.