LED light bulbs are manufactured with an average life span of 16 years and the bulb lifespans are known to follow an exponential distribution.

a. What is the probability that a bulb will last longer than 14 years?
b. What is the 50th percentile (or median) of bulb lifespans?

1 answer

P (x>14)=e^(-14/16)= 0.4169=41.6%

P(X>/=k)
Solve for K as K will be the median value.

e^(-k/16)=1/2
Shorthand to find the median of an exponential distr. is:
Meanxln(2)=k

meaning 16xln2=11.09
This is the value of a median, not a percentage.