Ecologists try to reduce the likelihood that variables not under the control of the experimenter will unduly influence the results of an experiment by
a. carefully setting up experiments so that the results are identical and do not need to be statistically analyzed to prove the result.
b. assigning treatments to subjects or plots methodically.
c. never performing the same experiment twice, but trying instead to improve each experiment.
d. replicating each treatment, including the control.

Ajustification for job training programs is that they improve worker productivity. suppose that you are asked to evaluate whether more job training makes workers more productive. however, rather than having data on individual workers, you have access to data on manufacturing firms in ohio. in particu- lar, for each firm, you have information on hours of job training per worker (training) and number of nondefective items produced per worker hour (output). (i) carefully state the ceteris paribus thought experiment underlying this policy question. (ii) does it seem likely that a firm’s decision to train its workers will be independent of worker characteristics? what are some of those measurable and unmeasurable worker characteristics? (iii) name a factor other than worker characteristics that can affect worker productivity. (iv) if you find a positive correlation between output and training, would you have convincingly established that job training makes workers more productive? explain.

You plan to invest some money in a bank account. which of the following banks provides you with the highest effective rate of interest? hint: perhaps this problem requires some calculations. bank 1; 6.1% with annual compounding. bank 2; 6.0% with monthly compounding. bank 3; 6.0% with annual compounding. bank 4; 6.0% with quarterly compounding. bank 5; 6.0% with daily (365-day) compounding.

T-comm makes a variety of products. it is organized in two divisions, north and south. the managers for each division are paid, in part, based on the financial performance of their divisions. the south division normally sells to outside customers but, on occasion, also sells to the north division. when it does, corporate policy states that the price must be cost plus 20 percent to ensure a "fair" return to the selling division. south received an order from north for 300 units. south's planned output for the year had been 1,200 units before north's order. south's capacity is 1,500 units per year. the costs for producing those 1,200 units follow