The life times, Y in years of a certain brand of lowgrade

lightbulbs follow an exponential distribution with a mean

of 0.75 years. A tester makes random observations of the life

times of this particular brand of lightbulbs and records them one

by one as either a success if the life time exceeds 1 year, or as a

failure otherwise.

Part a)

Find the probability to 3 decimal places that the first success

occurs in the fifth observation.

Part b)

Find the probability to 3 decimal places of the second success

occurring in the 8th observation given that the first success

occurred in the 3rd observation.

Part c) Find the probability to 2 decimal places that the first

success occurs in an odd-numbered observation. That is, the

first success occurs in the 1st or 3rd or 5th or 7th (and so on)

observation.