1 6. The random walk theory indicates that 0 a. investors can make money by purchasing stocks that are widely expected to earn substantial profits in the future. 0 b. while changes in the prices of specific stocks are difficult to predict, experts are able to forecast the future direction of broad stock market indexes with a high degree of accuracy. 1 c. changes in stock prices are driven by surprise occurrences that are difficult to predict. 2 d. managed mutual funds will persistently out-perform indexed funds