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.