Question

Five data entry operators work at the data processing department of the Birmingham Bank. Each day for 30 days, the number of defective records in a sample of 300 records typed by these operators has been noted. as follows: Sample No 1 No. Defectives Sample No. 11 12 13 No Defectives 5 2 No. Defectives 16 11 7 7 3 Sample No. 21 22 23 24 25 26 27 18 11 11 7 11 10 5 13 5 6 7 16 4 10 8 12 5 10 10 15 16 17 18 19 20 14 5 20 30 10 3 a) Establish Se upper and lower controllimit

Answer 1

(A)

1 7 4 Sample number Defective (np) 6 2 6 3 18 4 11 5 11 6 7 11 8 10 9 5 10 13 11 5 12 13 16 14 15 10 16 8 17 12 18 5 19 18 20 16 21 16 22 11 23 24 25 12 26 11 27 14 28 5 29 11 30 Sample size (n) 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 p[bar)= Sigma 3 Sigma Fraction defectivelp) 0.02 0.02 0.06 0.036667 0.036667 0.023333 0.036667 0.033333 0.016667 0.043333 0.016667 0.02 0.053333 0.013333 0.033333 0.026667 0.04 0.016667 0.06 0.053333 0.053333 0.036667 0.023333 0.023333 0.04 0.036667 0.046667 0.016667 0.036667 0.01 0.032778 0.01028 0.03084 0.063618 0.001938 7 7 نيا = UCLP LCLP

(B) The correct answer is (C) Since the percent of defective records cannot be a negative number.

(C) Since industry standard lies outside the limits of Birmingham bank hence birmingham bank is performing good.