A machine has a useful life of 4 to 9 years, and its life (in years) has a probability density function defined by

Find the probabilities that the useful life of such a machine selected at random will be the following.
(a) Longer than 6 years
(b) Less than 5 years
(c) Between 4 and 7 years
(d) Find the cumulative distribution function for this random variable.
(e) Use the answer to part (d) to find the probability that a randomly selected machine has a useful life of at most 8 years.

Transcribed Image Text:

f(t) 11 (₁ + 3) 1 V