H Ltd sells a line of goods under a six-month warranty. Any defect arising during that period is repaired free of charge. H Ltd has calculated that if all the goods sold in the last six months of the year required repairs the cost would be $2 million. If all of these goods had more serious faults and had to be replaced the cost would be $6 million.

The normal pattern is that 80% of goods sold will be fault-free, 15% will require repairs and 5% will have to be replaced.