Rather than have a global economy in which each country specializes entirely in what it produces most efficiently, most countries produce goods that they also import. (for example, the united states both produces and imports automobiles.) this can best be explained by the fact that: a. most countries use tariffs and quotas to restrict imports. b. most consumers prefer to buy imported goods. c. market economies cannot trade efficiently with non-market economies. d. as countries move toward specialization, opportunity costs change rather than remain constant.

Rate of return, standard deviation, coefficient of variation personal finance problem mike is searching for a stock to include in his current stock portfolio. he is interested in hi-tech inc.; he has been impressed with the company's computer products and believes hi-tech is an innovative market player. however, mike realizes that any time you consider a technology stock, risk is a major concern. the rule he follows is to include only securities with a coefficient of variation of returns below 1.07. mike has obtained the following price information for the period 2015 through 2018:hi-tech stock, being growth-oriented, did not pay any dividends during these 4 years. a. calculate the rate of return for each year, 2015 through 2018, for hi-tech stock. b. assume that each year's return is equally probable and calculate the average return over this time period. c. calculate the standard deviation of returns over the past 4 years. (hint: treat this data as a sample.) d. based on b and c determine the coefficient of variation of returns for the security. e. given the calculation in d what should be mike's decision regarding the inclusion of hi-tech stock in his portfolio?