A manufacturer of hydraulic equipment is trying to determine whether it should use monofl ange double block and bleed (DBB) valves or a multi-valve system (MVS) for chemical injection. The costs are shown below. Use an AW-based rate of return analysis and a MARR of 18% per year to determine the better of the two options. DBB MVS First cost, $ 40,000 71,000 Annual cost, $ per year 60,000 65,000 Salvage value, $ 0 18,000 Life, years 2 4

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.