Question: 10 light bulbs were tested over a 100 hours period...

10 light bulbs were tested over a 100 hours period. Some units failed as follows: after 16, 18, 22, 24, 27, 38 and 98 hours, respectively. The remaining units performed satisfactorily until the end of the test. The failure rate per hour is

Select one: a. 0.01049 b. 0.00484 c. 0.00765 d. 0.01289