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.
It reminded me of the stock exchange, with a bull market in progress. The word is used very frequently with reference to the market, a bull market meaning a rising market. When stocks are moving up steadily in a bull market, people closely connected with the market expect a reaction and watch for it.