The rate of depreciation (in dollars per year) for a certain truck is given by the function below, where t is in years and tequals0 is the year of purchase. f(t)equalsstartfraction 5800 (0.4 plus 0.24 t )over (1 plus 0.4 t plus 0.12 t squared )squared endfraction (a) find the total depreciation at the end of 3 years. (b) how long will it take for the total depreciation to be at least $2900?

Suppose an economist believes that the price level in the economy is directly related to the money supply, or the amount of money circulating in the economy. the economist proposes the following relationship: p=a x m - p=price level - m=money supply - a=a composite of other factors, including real gdp, that change very slowly over time. how might an economist gather empirical data to test the proposed relationship between money and the price level? an economist would persuade the federal reserve to change the money supply to various levels, and observe the resulting changes in the price level. unlike researchers in the hard sciences, economists cannot study complex relationships using data. economists do not usually develop theoretical models of the economy but only analyze summary statistics about the current state of the economy. an economist would look for data on past changes in the money supply, and note the resulting changes in the price level

The uptowner just paid an annual dividend of $4.12. the company has a policy of increasing the dividend by 2.5 percent annually. you would like to purchase shares of stock in this firm but realize that you will not have the funds to do so for another four years. if you require a rate of return of 16.7 percent, how much will you be willing to pay per share when you can afford to make this investment?

Reliability and validity reliability and validity are two important considerations that must be made with any type of data collection. reliability refers to the ability to consistently produce a given result. in the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways. unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. to illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. if the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. while the scale is highly reliable in producing consistent results (e.g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. this is where validity comes into play. validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. while any valid measure is by necessity reliable, the reverse is not necessarily true. researchers strive to use instruments that are both highly reliable and valid.