The guaranteed average life of a certain type of electric bulbs is 1500 hrs with a standard deviation of 120 hrs. It is decided to sample the output so as to ensure that 95% of the bulbs do not fall...

Extracted text: The guaranteed average life of a certain type of electric bulbs is 1500 hrs with a standard deviation of 120 hrs. It is decided to sample the output so as to ensure that 95% of the bulbs do not fall short of the guaranteed average by more than 2-5%. What willI be the minimum sample size.