The following table shows the monthly defect rate for a product at a manufacturing company. month 1 2 3 4 5 6 7 8 9 10 11 12 number of defects (per 1,000 units) 18 21 22 25 28 25 24 18 20 21 26 28 the production manager is going to present this information to the company's board of directors. which graph should the manager use to best emphasize that the number of defects has remained relatively consistent throughout the year?