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.
: something (such as a fence or natural obstacle) that prevents or blocks movement from one place to another. Concrete barriers surround the racetrack to protect spectators. The tree's roots serve/act as a barrier against soil erosion. The mountain range forms a natural barrier between the two countries.