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.
The greatest mountain systems are the Alps of Europe, the Andes of South America, the Himalayas of Asia, and the Rockies of North America. Notable single peaks in these systems include Mont Blanc (Alps), Aconcagua (Andes), Everest (Himalayas), and Elbert (Rockies). mountain is any landmass on Earth 's surface that rises to a great height in comparison to its surrounding landscape. Mountains usually have more-or-less steep sides meeting in a summit that is much narrower in width than the mountain's base.