Many financial economists believe that the random walk model is a good description of the logarithm of stock prices. It implies that the percentage changes in stock prices are unforecastable. A...

Many financial economists believe that the random walk model is a good
description of the logarithm of stock prices. It implies that the percentage
changes in stock prices are unforecastable. A financial analyst claims to have
a new model that makes better predictions than the random walk model.
Explain how you would examine the analyst’s claim that his model is superior?