Discussion:
Q: According to the National Association of Homebuilders, the average life expectancies of a dishwasher and a garbage disposal are about the same: 10 years. Assume that their finding was based on a sample of n1 = 60 dishwashers and n2 = 40 garbage disposals, and that the corresponding sample standard deviations were s1 = 30 years and s2 = 3.7 years. Using the 0.02 level of significance, examine whether the population standard deviations for the lifetimes of these two types of appliances could be the same.