In: Statistics and Probability
Perimeter Road has 4 streetlights. A streetlight burns out after an average of 100 days of use (exponentially distributed). It takes an average of 10 days to replace a burned-out street lamp (exponentially distributed). Model the number of functioning streetlights as a birth-and-death process.
(a) What is the long-run proportion of time that all streetlights are burned out?
(b) On average how many streetlights are illuminating the Perimeter Road?