Why is there scarcity even in an affluent country like the United States

True or false: a fitted model with more predictors will necessarily have a lower training set error than a model with fewer predictors.

How did the contribution of the goods producing sector to gdp growth change between 2010 and 2011 a. it fell by 0.3%. b. it fell by 2.3%. c. it rose by 2.3%. d. it rose by 0.6%. the answer is b

You decide to invest in a portfolio consisting of 25 percent stock a, 25 percent stock b, and the remainder in stock c. based on the following information, what is the expected return of your portfolio? state of economy probability of state return if state occurs of economy stock a stock b stock c recession .16 - 16.4 % - 2.7 % - 21.6 % normal .55 12.6 % 7.3 % 15.9 % boom .29 26.2 % 14.6 % 30.5 %