Life (in hour) of 10 bulbs from each of four different companies A, B, C and D are given below in the table.
`{:(A,B,C,D),(120,700,950,530),(1600,502,330,650),(280,1430,1200,720),(420,625,500,550),(800,780,445,748),(770,335,1260,570),(270,224,375,635),(455,1124,1130,804),(150,473,185,500):}`
By using the coefficient of range find which company has shown the best consistency in its quality?

Options

A. A
B. B
C. C
D. D

Answer

D

Explanation

(i) Find the coefficient of range of A, B, C and D and compare.
(ii) `"Coefficient of range" = ("Maximum value - Minimum value")/("Maximum Value + Minimum value")`
(iii) Find the coefficient of range of A, B, C and D.
(iv) The least coefficient of range implies good performance.