You conducted a study on the efficacy of seatbelt use against the incidence of a skeletal fracture among persons involved in an automobile crash. the cases in each study were persons who sustained a fracture in a car crash. controls were persons in crashes who did not sustain a fracture (assume all other characteristics and exposures were identical). 1,000 cases and 1,000 controls were enrolled in this study; of the cases, 322 had worn seat belts whereas 500 of the controls had. what is the study design?

Which of the following is one of the five fundamental questions? which products will be in scarce supply and which in excess supply? who should appoint the head of the central bank? how much should society save? correct what goods and services will be produced?

Exercise 2-12 cost behavior; high-low method [lo2-3, lo2-4] speedy parcel service operates a fleet of delivery trucks in a large metropolitan area. a careful study by the company’s cost analyst has determined that if a truck is driven 120,000 miles during a year, the average operating cost is 11.6 cents per mile. if a truck is driven only 80,000 miles during a year, the average operating cost increases to 13.6 cents per mile. required: 1.& 2. using the high-low method, estimate the variable and fixed cost elements of the annual cost of truck operation. (round the "variable cost per mile" to 3 decimal places.)

Provide three examples of how the purpose of investing is different than the purpose of saving