Life of bulbs produced by two factories A and B are given below:

The bulbs of which factory are more consistent from the point of view of the length of life?

For Factory A

Now, N=120,

Mean

Variance = 12097

Standard Deviation

SD = 109.98

Coefficients variation =

Cv=13.61

For Factory B

Now, N=120,

Mean

Variance = 11400

Standard Deviation

SD = 106.77

Coefficients variation =

Cv=14.29

Since, the coefficient of variation of factory B is greater than the coefficient of variation of factory A,

Hence, This means bulbs of factory A are more consistent from the point of view of the length of life.