Introduction to Statistics and Probability

Depending on how data can be used statistics is sometimes divided in to two main areas or branches.1. Descriptive Statistics: is concerned with summary calculations graphs charts and tables.2. Inferential Statistics: is a method used to generalize from a sample to a population. For example the average income of all families (the population) in Ethiopia can be estimated from figures obtained from a few hundred (the sample) families.• It is important because statistical data usually arises from sample.• Statistical techniques based on probability theory are required.