Question

In a manufacturing process, 4 items are inspected every hour for 10 consecutive hours. The measured quality characteristic (in mm) is given below:

Hour 1 2 3 4
1 50 52 51 49
2 51 50 53 52
3 49 50 48 51
4 52 54 53 51
5 50 49 51 50
6 53 52 54 55
7 48 49 50 47
8 51 52 50 51
9 54 55 53 54
10 50 51 49 50

Construct control chart for variability and mean and comment on the state of statistical control. If the process is out of control, obtain revised control limits.

19 Jan 2026
Answer :
Word Count : 517
For each hour, the sample size is n = 4. Hence an (\bar X)-chart and an R-chart are appropriate. First, compute the sample mean and range for each hour. Hour 1: values 50, 52, 51, 49 (\bar X_1 = (50+52+51+49)/4 = 50.5), (R_1 = 52-49 = 3) Hour 2: 51, 50, 53, 52 (\bar X_2 = 51.5), (R_2 = 53-50 = 3) Hour 3: 49, 50, 48, 51 (\bar X_3 = 49.5), (R_3 = 51-48 = 3) Hour 4: 52, 54, 53, 51 (\bar X_4 = 52.5), (R_4 = 54-51 = 3) Hour 5: 50, 49, 51, 50 (\bar X_5 = 50.0), (R_5 = 51-49 = 2) Hour 6: 53, 52, 54, 55 (\bar X_6 = 53.5), (R_6 = 55-52 = 3) Hour 7: 48, 49, 50, 47 (\bar X_7 = 48.5), (R_7 = 50-47 = 3) Hour 8: 51, 52, 50, 51 (\bar X_8 = 51.0), (R_8 = 52-50 = 2) Hour 9: 54, 55, 53, 54 (\bar X_9 = 54.0), (R_9 = 55-53 = 2) Hour 10: 50, 51, 49, 50 (\bar X_{10} = 50.0), (R_{10} = 51-49 = 2) Now compute the overall averages. [ \bar{\bar X} = \frac{50.5+51.5+49.5+52.5+50.0+53.5+48.5+51.0+54.0+50.0}{10} = \frac{510.0}{10} = 51.0 ] [ \bar R = \frac{3+3+3+3+2+3+3+2+2+2}{10} = \frac{26}{10} = 2.6 ]
_______ _____ _________ ____ ___ _______ ________ __________.
____ ______ ________ _____ __________ _______ ________.
__________ _________ ___ ______ ____ __________ _____.
______ ____ __________ ___ ___ _________ ___ __________ __________ ____.
_____ ________ ______ _________ _______ _______ __________ ______.
___ _______ _____ ______ ______ _________ _________ _____ _________ ________.
___ _________ ______ ________ ____ _____.
_________ ________ _______ _______ _________ __________ ____ ___ __________.
_________ ____ _______ ______ _________ _______ _______ _____ ___.
_____ ___ _________ ________ ______ ___ _________ ______ ________ ____ ___.
_______ ___ ________ _________ _______ ______ ________ _________ ___ _____ ________.
______ __________ _______ ______ ____ _______ _____ ________ ____ ____.
___ ____ ___ ________ _____ ______ ______ _____ _________ ________ ________ _______.
__________ ___ _________ ___ ____ __________ _____ __________ ___.
___ _________ ________ __________ _______.
__________ ___ ________ ______ __________ ________ ______ ____ ________ _______ ________ ________.
_______ ____ __________ __________ ____ ____ ____.
_________ _______ __________ ______ _______ ____ ___ __________ _______ ______.
__________ _____ ______ ______ ____ ___ ___ ______ __________.
________ _________ __________ ______ _________.
______ ___ _________ __________ _____.
____ _________ _____ __________ _________ _______ ________ __________ ____ _________.
__________ _________ _________ __________ ____ ___ _____ __________ ____.
_________ ______ __________ _________ _________ ______ ___.
_______ _________ __________ ______ ________ ________ ___ _________ _____ _____ _________ __________.
_________ _____ _____ _________ ____ _________ ______ _________ _______ _______ __________ ______.
__________ _________ ____ _____ ____ ___ ___ ___ ____ ________.
___ ___ ______ ___ ____ __________ ________ ________ _______.
_________ ____ ___ _________ ___ _____ _______ ______ _____ _________ _____ ______.
__________ ________ _______ ________ _________ __________ ___ ________ _______ __________ ______.
_________ ___ _______ _________ ______.
_________ _____ _____ ___ __________.
___ ___ ____ _______ ____ ______ ___ __________ ___ ____ ________.
__________ ______ _________ ______ __________ ______ __________ ____ ____ _________ ___ _________.
_______ ______ _________ ________ __________.
IGNOU ACADEMY
Your IGNOU journey, made easier.
  • Solved Assignments
  • Study Notes
  • Guess Papers
  • Question Papers
Skip in 10
Top
📞
Call Support Instant phone assistance IGNOU MSTE 1 2026 - In a manufacturing process, 4 items are inspected every hour for 10 co | IGNOU Academy
→
🟢
WhatsApp Chat Fast live messaging
→
Email Us Business enquiries & support
→