. From June 2008 oil was at a high of $144.78 per barrel. During the period from April 2011 until July of 2014, the price of oil hovered between about $115.32 per barrel and about $105.22 a barrel. Then, starting in August 2014 oil began a precipitous fall in price from the $105.22 to $33.62 a barrel in January 2016. Although the U. S. has great amounts of oil that can be brought out of the ground by “fracking,” by the beginning of 2016 many of the workers in the U. S. oil exploration and drilling industry were out of work and tremendous amounts of oil exploration equipment was sitting in the equivalent of “used car lots” to be sold. a. Which of the economic principles best describes this situation? b. Using the principle you have selected, describe the chain of links that best explains how the falling international oil prices caused U. S. workers to be laid off and available U. S. oil to be left in the ground.

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.

Chang corp. has $375,000 of assets, and it uses only common equity capital (zero debt). its sales for the last year were $595,000, and its net income was $25,000. stockholders recently voted in a new management team that has promised to lower costs and get the return on equity up to 15.0%. what profit margin would the firm need in order to achieve the 15% roe, holding everything else constant? a. 9.45%b. 9.93%c. 10.42%d. 10.94%e. 11.49%

Which is cheaper: eating out or dining in? the mean cost of a flank steak, broccoli, and rice bought at the grocery store is $13.04 (money.msn website, november 7, 2012). a sample of 100 neighborhood restaurants showed a mean price of $12.75 and a standard deviation of $2 for a comparable restaurant meal. a. develop appropriate hypotheses for a test to determine whether the sample data support the conclusion that the mean cost of a restaurant meal is less than fixing a comparable meal at home. b. using the sample from the 100 restaurants, what is the p-value? c. at a = .05, what is your conclusion? d. repeat the preceding hypothesis test using the critical value approach