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.
A bull market is a market with high esteem and high optimism. With a positive outlook for the future, the bull market most often refers but non exclusively to the market pushing equity prices, but also other financial instruments such as bonds, currencies and asset backed securities. Hence gains the name bull for the aggressive nature of the market.