nb plastics uses injection molds to produce plastic parts that range in size from a marble to a book. parts are pulled off the press by one operator and passed on to another member of the team to be finished or cleaned up. this often involves trimming loose material, drilling holes, and painting. after a batch of parts has completed its cycle through the finishing process, a sample of five parts is chosen at random and certain dimensions are measured to ensure that each part is within tolerances. this information (in mm) is recorded for each of the five pieces and evaluated. create a histgram. are the two operators trimming off the same amount of material? how do you know?