A METHOD OF RATING MANUFACTURED PRODUCT 



361 



Illustrative Examples 



Example I — Monthly Rate for General Information Purposes Showing 

 Quality of Finished Product 

 This example presents a monthly quality report for a kind of tele- 

 phone apparatus which is manufactured in large quantities for use in 



YEAR 22 £3 24 25 



1926 



1927 



♦ 10 

 



Id 



Sj-io 



-20 



-30 



~ T 





Total 



Computation of Control Limits. — 



k = 



2.9018 



2.02380 



1 



Base Period Demerits per Unit 



= 1.109, Re = 0, K = 3, 



a^^ = 10^ Y'2g(^jJ = 10(1.109) V.02380 = 1.711. 



Limits Rl = i?e ± Kor,. 

 = ±3(1.711) 



= +5.133 and -5.133. 



Fig. 6 — A typical rating chart with variable control limits 



central office exchanges. The data given in Fig. 5 represent a portion 

 of the summarized results of inspection. The detailed information 

 24 



