Statistics basics 1st and 3rd

Unit 7

Statistics

Mathematics for the states

Statistics is a part of Mathematics that concerns the collection, organization, analysis, interpretation and presentation of data.

1. Statistical Concepts.

The set of individuals or objects the statistical study addresses is called Population. Statistical data are obtained from the population.

Sometimes the population is too big to study all individuals. In this case we pick randomly some individuals. This subset of individuals is called sample.A sample must be representative of the population. To make this sure, the sample must be chosen randomly and must be big enough. The number of individuals chosen for the sample is called the sample size.

The features or characteristics we want to study in the populations are called the statistical variables. Sometimes the variables can be just qualities not suitable to be measured with numbers. These type of variables are called qualitative variables. Some other times, the variables can be measured with numbers. In this case they are called quantitative variables.

Sometimes, quantitative variables accept all types of numbers, integers or decimals. They are called continuous variables. Some other accept only certain numbers, usually integers. They are called discrete variables.

2. Statistical Parameters.

The amount of data obtained from the study of populations or samples is usually very large. In order to handle these data in a proper way, they have to be summarized into a smaller set of numbers. These numbers are the statistical parameters.

The most common statistical parameter is the mean or average. But there are others that you will learn in this unit and in other future courses.like median, mode, range, standard deviation and variation coefficient.

3. Statistical Graphics.

Beside the statistical parameters, the data can be summarized in different types of statistical graphics. In this unit you will learn how to create your own graphics.

This has been all regarding the theory of this unit. Keep on doing the activities and you will learn a lot of usefuls things.