A plumbing company receives call-outs during the working day at an average rate of 2.4 per hour.
Find the probability that the company receives exactly 7 call-outs in a randomly selected 3 -hour period of a working day.
The company has enough staff to respond to 28 call-outs in an 8 -hour working day.
Show that the probability that the company receives more than 28 call-outs in a randomly selected 8 -hour working day is 0.022 to 3 decimal places.
In a random sample of 100 working days each of 8 hours,
find the expected number of days that the company receives more than 28 call-outs,
find the standard deviation of the number of days that the company receives more than 28 call-outs,
use a Poisson approximation to estimate the probability that the company receives more than 28 call-outs on at least 6 of these days.