The Golden Retriever Club of America conducted a study of 64 golden retrievers, and found the average age at death in the sample to be 11.0 years old. Let’s assume the standard deviation of golden retriever lifespan is known to be 1.2 years (this is consistent with studies and with some other dog breeds). Required:
Give three confidence interval estimates for the unknown mean age at death for golden retrievers: first using 90% confidence, then 95%, and finally 99%.

Captain john's yachts, inc., located in fort lauderdale, florida, rents three types of ocean-going boats: sailboats, cabin cruisers, and captain john's favorite, the luxury yachts. captain john advertises his boats with his famous "you rent"we pilot" slogan, which means that the company supplies the captain and crew for each rented boat. each rented boat has one captain, of course, but the crew sizes (deck hands, galley hands, etc.) differ. the crew requirements, in addition to a captain, are one for sailboats, two for cabin cruisers, and three for yachts. ten employees are captains, and an additional 18 employees fill the various crew positions. currently, captain john has rental requests for all his boats: four sailboats, eight cabin cruisers, and three luxury yachts. if captain john's daily profit contribution is $50 for sailboats, $70 for cruisers, and $100 for luxury yachts, how many boats of each type should he rent?