I. When the sum of the residuals is greater than zero, the data set is nonlinear. II. A random pattern of residuals supports a linear model. III. A random pattern of residuals supports a non-linear model.
bull market definition. A market, especially a stock market, characterized by rising prices; the opposite of a bear market. We can always go back to worrying; we are still in a bull market for fear.
Lesson 1: What does a bull market look like? A bull market is a period of rising stock prices and greater investor confidence in the market, so named because of a bull's tendency to strike upward when it attacks, knocking foes into the air. In slightly more specific terms, a bull market is a period of sustained growth -- major indexes gain at least 20% -- that lasts at least several months before reversing course.