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.
In a bull market, stocks show a tendency to go up in price over a period of time. This period can be weeks, months or years. It's not an exact term. Instead, it refers more to confident sentiment among investors. In practice, it means the market has more buyers than sellers. When demand exceeds supply, prices rise.