Name That Distribution!

Exercises on
Discrete distributions
A traffic control engineer reports that 75%
of the vehicles passing through a
checkpoint are from within the state. What
is the probability that fewer than 2 of the
next 5 vehicles are from out of state?
Suppose that a computer programmer, on
average, makes 3 errors in 500 lines of
code. What is the probability that the
programmer will make no errors in 250
lines of code?
Six is the average number of oil tankers
arriving each day at a certain port city.
The facilities can handle at most 10
tankers per day. What is the probability
that on a given day, some tankers will
have to be turned away?
An Air Force intercept squadron consists of
16 planes that should always be ready for
immediate launch. However, there is a
probability of 0.25 that the engine of each
plane will not start at a given attempt. If
this happens, the mechanics must wait 5
minutes before trying to start the engine
again. What is the expected number of
planes to immediately launch?
The number of cracks in a section of
interstate highway averages 2 per mile.
What is the probability that there will be at
least 1 crack in the next ½ mile of the
A particularly long traffic light on your way
to work in the morning is green 20% of
the time that you approach it. Over 20
mornings, what is the probability that the
light is green on exactly 4 days?