Question

The following data 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
Frequency	10	35	52	61	38	29

Determine the modal lifetimes of the components.

Answer 1

Here. the maximum class frequency is 61 and the class corresponding to this frequency is 60-80. So, the modal class is 60-80.

Hence, modal lifetime of the components  is 65.625 hours.