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.
When gravity (downwards) is the direction of maximum stress and one or other of the horizontal stresses decays slightly, fault block mountains form. When gravity (downwards) becomes the lowest stress, reverse faults (thrusts) and fold mountains are formed.