In the hypothesis testing approach of Jerzy Neyman and Egon Pearson, a null hypothesis is contrasted with an alternative hypothesis, and the two hypotheses are distinguished on the basis of data, with certain error rates. Proponents of each approach criticize the other approach.
In geography, relief refers to the highest and lowest elevation points in an area. Mountains and ridges are typically the highest elevation points, while valleys and other low-lying areas are the lowest. Relief is essential to understanding the topography of an area.
Fold mountain. Fold mountains are mountains formed mainly by the effects of folding on layers in the upper part of the Earth's crust. The term is rather out of date, though still fairly common in physical geography literature. In the time before plate tectonics became well understood, the term was used for mountain belts, such as the Himalayas. These mountain ranges are not caused by the folding of the earth's crust. The main mechanism causing a thickening of the crust at these sites of continent-continent collision along a convergent boundary is thrust faulting. Fold mountains are formed when two tectonic plates move together (a convergent plate boundary).