Yilekal Yewlu

Introduction to Statistics and Probability Yilekal Yewlu

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.