Question

The following data is gives the information on the observed lifetimes (in hours) of 225 electrical components:

Lifetimes (in hours)	0−20	20−40	40−60	60−80	80−100	100−120
No. of components	10	35	52	61	38	29

Determine the modal lifetimes of the components.

Answer 1

Lifetimes (in hours)	0−20	20−40	40−60	60−80	80−100	100−120
No. of components	10	35	52	61	38	29

Here, the maximum frequency of electrical components is 61 so the modal class is 60−80.

Therefore,

Thus, the modal lifetimes of the components is 65.625 hours.