Question

The length of a time a system is"down" (ie broken) is described approximately by the probability distribution (see table) Assume that these downtimes are exact. That is , there are three types of easily recognized problems that always take this long (5, 30 or 120 minutes) to fix.

a. What kind of probability distribution does this table represent?

b. Find the mean downtime.

c. Find the standard deviation of the downtime.

d. What is the probability that the downtime will be greater than 10 minutes, according to the table?

Problem	Downtime (mins)	Probability
Minor	5	0.60
Substantial	30	0.30
catastrophic	120	0.10

Answer 1