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Five data entry operators work of Data Processing department each day for 20 day

ID: 375034 • Letter: F

Question

Five data entry operators work of Data Processing department each day for 20 days the number of defective records in a sample of 250 records typed by these operators has been noted, as follows: No 12 20 Sample No Sample No. Defective No. Defective 12 13 2 10 10 4 4 15 16 17 18 19 20 12 4 6 25 6 6 13 10 1. What is the size of each sample (i.e. what is the sample size)? 2. How many samples does this QC problem have? 3. The appropriate chart for this problem is A. Mean chart B. Range chart C. P-chart D. C-chart E. None of the above 4. What is the proportion of defective records for the 20th sample? 5. What is the overall proportion of defective records (average sample proportion)?

Explanation / Answer

Please find answers to first 5 questions :

SIZE OF EACH SAMPLE = 250

NUMBER OF SAMPLES THIS QC PROBLEM HAS =20

APPROPRIATE CHART FOR THIS PROBLEM IS : p CHART

PROPORTION OF DEFECTIVE RECORD FOR2OTH SAMPLE = 25/250 = 0.1

Total number of defective record = Sum of all numbers as provided in the problem = 192

Total number of items = 250 items / sample x 20 samples = 5000

Overall proportion of defective records = 192/5000 = 0.0384

OVERALL PROPORTION OF DEFECTIVE RECORDS =0.0384

SIZE OF EACH SAMPLE = 250

NUMBER OF SAMPLES THIS QC PROBLEM HAS =20

APPROPRIATE CHART FOR THIS PROBLEM IS : p CHART

PROPORTION OF DEFECTIVE RECORD FOR2OTH SAMPLE = 25/250 = 0.1