56.18 Five data entry operators work at the data processing department of the Royal Bank. Each day for 30 days, the number of defective records in a sample of 250 records typed by these operators has been noted, as follows: Sample No. Sample No. Sample No. No. Defective No. Defective No. Defective 1 18 11 17 21 7 5 12 12 22 5 16 13 6 23 19 4 4 14 7 24 10 5 11 15 13 25 11 nm 000 6 8 16 10 26 8 7 12 17 4 27 12 4 18 6 28 9 6 19 12 29 6 10 16 20 3 30 13 a. Establish 30 upper and lower control limits. b. Why can the lower control limit not be a negative number? c. The industry standards for the upper and lower control limits are 0.10 and 0.01, respectively. What does this imply about Royal Bank's own standards? PX