Develop a Pareto chart of the following causes of poor grades on an exam: REASON FOR POOR GRADE and FREQUENCY Insufficient time to complete = 15 Late arrival to exam = 7 Difficulty understanding material = 25 Insufficient preparation time = 2 h Studied wrong material = 2 Distractions in exam room = 9 Calculator batteries died during exam = 1 Forgot exam was scheduled = 3 Felt ill during exam = 4