A rational decisionmaker A. ignores marginal changes and focuses instead on “the big picture.”
B. takes an action only if the combined benefits of that action and previous actions exceed the combined costs of that action and previous actions
C. ignores the likely effects of government policies when he or she makes choices
D. takes an action only if the marginal benefit of that action exceeds the marginal cost of that action

Jagjit company designs and builds retaining walls for individual customers. on august 1, there were two jobs in process: job 93 with a beginning balance of $8,650, and job 94 with a beginning balance of $7,270. jagjit applies overhead at the rate of $9 per direct labor hour. direct labor wages average $16 per hour. data on august costs for all jobs are as follows:

The hawthorne works was a large western electric factory with 45,000 employees. during the 1920s and 1930s, hawthorne works was the site of some well-known industrial studies. in one of the studies, researchers investigated the impact of different working conditions on worker productivity. prior to the start of the study, researchers secretly measured workers' productivity for several weeks. then researchers chose two workers, who then chose their own teams. the teams were separated from the general workforce and completed their work in different experiment rooms where the researchers could observe them more easily. over a 5-year period researchers manipulated the structure of the workday for each team (number and duration of breaks and number of hours per shift). for each of these changes in working conditions, the researchers measured the effect on productivity. for some conditions, such as frequent short breaks, workers rebelled by intentionally decreasing productivity.why did the researchers secretly measure the workers' productivity before creating the two treatment groups? a, to create similar treatment groups so that a cause-and-effect relationship could be establishedb, to draw conclusions about the productivity of all workers in the plant based on the test groupsc, to directly control for confounding variablesd, to provide a baseline for measuring worker productivity

Franklin painting company is considering whether to purchase a new spray paint machine that costs $4,800. the machine is expected to save labor, increasing net income by $720 per year. the effective life of the machine is 15 years according to the manufacturer’s estimate. required determine the unadjusted rate of return based on the average cost of the investment.