1. Quality-control studies for dependable dishwashers show that the lifetime of a dishwasher
follows a normal distribution with mean u=8 years and standard deviation o' =1.2 years. The
company will replace any dishwasher that fails during the gurantee period. How long should the
company's dishwashers be quaranteed if the company wishes to replace no more than 2% of the
dishwashers?
Please show work
Solution
p(z