1. Suppose a manufacturer of light bulbs produces a 75-watt bulb that burns a mean of 4,200 hours before it burns out. It has a standard deviation of 300 hours. What warranty life (in terms of hours) should the manufacturer offer if they want to replace no more than 1% of the bulbs sold?
   1. 1,200
   2. 3,500
   3. 4,150
   4. 7,320
2. The annual rate of return on an investment is normally distributed with a mean of 10% and a standard deviation of 12%. What is the probability that the investment loses money next year?
   1. 0.8567
   2. 0.7033
   3. 0.2033
   4. 0.1067
3. Valentine’s Day is traditionally the busiest day for florists, with orders spiking by 300% above what is traditionally the industry average for orders to be delivered on a single day. The Arkansas State Small Business Development Center published data indicating that florists in NW Arkansas have an average of 26 deliveries per day (excluding Valentine’s Day) with a standard deviation of 1.5 deliveries. 90% of florists in NW Arkansas would have MORE than about how many Valentine’s Day deliveries?
   1. 24
   2. 26
   3. 28
   4. 30

4. A sociologist knows the national average that couples are engaged prior to their first marriage is 265 days with a standard deviation of 49 days. George and Molly are dating. Neither of them has been married before and they were engaged for 200 days before their wedding day. What percent of couples have a SHORTER engagement?
   1. 1.33%
   2. –1.33%
   3. 40.82%
   4. 9.2%
5. The United States Postal Service (USPS) now offers a service that allows customers to ship packages at a flat rate based on box size (small, medium, large) rather than by weight. The USPS records the weight of all small packages shipped using this new service and finds a normally distributed variable with a mean of 6.9 pounds and a standard deviation of 10 ounces (.63 pounds). The lightest 15% of packages shipped using the small size box weigh less than:
   1. 7.56 pounds
   2. 7.15 pounds
   3. 6.65 pounds
   4. 6.24 pounds
6. Customers who use automatic teller machines (ATM) can perform several transactions quickly and efficiently. A banking consultant has noted that the times to complete a transaction are normally distributed with a mean of 34 seconds and a standard deviation of 4 seconds. What proportion of ATM customers take more than 31 seconds to do their banking?
   1. About 23%
   2. About 27%
   3. About 73%
   4. About 77%
7. Frank sells hotdogs from a cart on campus. When he makes too many or too few burritos, he loses money. Over the years, Frank has found that the average daily demand for hotdogs is 250 with a standard deviation of 12. Frank wants to stock enough hotdogs so that he has an 80% chance of having enough to meet demand. How many hotdogs should he stock?
   1. 230
   2. 240
   3. 260
   4. 291

Answer rating: 100% (QA)

0 Meau 4 4200 hours 50300 hours P X 4200 ... View the full answer