The symmetric, unimodal, bell curve is ubiquitous throughout statistics. Indeed it is so common, that people often know it as the normal curve or normal distribution. The term normal means that it is not at the usual place. This distribution was used in so many ways, from the real integers, which includes: the characteristic of living things( weight, height, human, animals, etc.), measuring mistakes in an experiment, Score variable in a test.
Many variables are nearly normal, but none are exactly normal. Thus the normal distribution, while not perfect for any single problem, is very useful for a variety of problems. We will use it in data exploration and to solve important problems in statistics.
