Management at the local Speedy Lube has found that it takes…

Management at the local Speedy Lube has found that it takes an average of 17 minutes, with a standard deviation of 2.5 minutes, in order to fully complete an oil change service. Management decides to take advantage of the quick service provided with a marketing campaign that promises “50% off your bill if we take longer than 20 minutes”.   After several months, management sees that they are giving out too many discounts, and they want to revamp the program.  They find that this program will be very profitable if they give the discount to no more than 3% of their customers.  If this is the case, how long should they make the guaranteed time limit?

Are young couples who marry or cohabitate more likely to gai…

Are young couples who marry or cohabitate more likely to gain weight than those who stay single? Researchers followed 8000 men and women for 7 years.  At the start of the study, none of the participants were married or living with their romantic partner.  The researchers found that women who married or cohabitated during the study gained 0 more pounds than single women, and married or cohabitating men gained, on average, 6 pounds more than single men.    What conclusions can be made based on the results of this study?