# Descriptive statistics

One of the most important statistical studies that should be carried out is descriptive statistics, since it is the best option that exists to be able to obtain valuable ideas about specific data and in this way avoid errors. This procedure belongs to the branch of Statistics which is a branch of mathematics that is responsible for collecting, interpreting and organizing all data.

## What is descriptive statistics?

Descriptive statistics is one of the branches of statistics that is responsible for collecting data and then analyzing and characterizing them , all with the aim of being able to describe their characteristics and the type of behavior they have using tables and graphs .

• Definition
• Descriptive statistics characteristics
• History
• Descriptive statistics applications
• Types
• Method
• Basic concepts
• Importance of descriptive statistics
• Examples

## Definition

Descriptive statistics is a group of graphical and numerical techniques that are used to make a description and analysis of a data set, but without making any kind of inference to the population to which it belongs.

## Descriptive statistics characteristics

The main characteristics that can be found in descriptive statistics are mentioned below:

• It is used to be able to describe a certain set of data .
• The use of qualitative and quantitative variables is necessary to obtain accurate data.
• Use the measure of dispersion to find out if the distance between the data and the mean.
• The information obtained through it can be represented using tables and graphs .
• It is an effective method to organize the data you have.
• Through it, conclusions can be drawn .
• Observation is also used for data collection.

## History

The history of descriptive statistics dates back to very ancient times and it was a process that took many years to develop and evolve, a process that goes from the simple collection of data to the rigorous interpretation of the same that exists today. Practically since the beginning of civilization , forms of statistics have been presented through graphic representations and symbols in such a way that we can say that this science is as old as writing.

It is believed, according to experts, that it had its origin in ancient Egypt where the pharaohs collected data related to crops, populations and wealth, all this to be prepared for the construction of the pyramids. In 3000 BC the Babylonians also began to collect data on agriculture and bartering. The first population censuses using this statistic were done in China and the Roman Empire was the first government that was able to use science using the collection of large amounts of population data. By the ninth century, censuses beganand during the 15th, 16th and 17th centuries the great scientists of the time began to introduce the scientific method .

## Descriptive statistics applications

There are many areas of work that need the collection of information and descriptive statistics are used for this. It is a science that can be applied in the fields of demography , economics and sociology , but it can also be used in the field of sciences such as physics and medicine . In the sciences it can be used to present models of physics and in the social and economic sciences to carry out studies of demography and sociology .

In medicine , this type of statistics makes it possible to make models that show the progress of a certain disease or to create mortality lists. In the industry it can be used to carry out follow-ups, to find improvements in the field of work and to know the health situation of workers, including age. It is the indicated method to be able to carry out statistical quality controls.

## Types

There are two types of descriptive statistics: measures of central tendency and measures of variability, which are explained below.

#### Measure of central tendency

This measure corresponds to the central part of the data set and is carried out with the aim of being able to make a summary of the information obtained from the sample in order to have more and better knowledge. To measure the central tendency , arithmetic , the mode, and the median are used .

#### Mean / average

This is a centralized trend of the data , in other words, it is a quantity that is used to distribute the different data obtained. It is a number that has the ability to estimate the total value that belongs to the data set.

## Method

The methods that can be used to obtain good descriptive statistics are the following:

#### Graphical methods

Graphic methods include images that have the ability to improve understanding of variables and their relationships. They have the ability to visually represent the data obtained. Examples of this type of method are histograms, graphs, and sociograms.

#### Central tendency measurement method

This is the most basic method, but it can also provide the most characteristics for a given population. To carry it out, the mean, median and mode are used.

#### Dispersion measurement method

These measures are used to obtain information regarding the dispersion suffered by the values ​​within a variable. It can be obtained using measures such as range, variation, and standard deviation.

#### Association measures

These measures can indicate when two variables have a relationship and in general this data can be obtained through correlation and chi square.

## Basic concepts

The basic concepts that can be found within descriptive statistics are the following:

• Population : set of individuals that need to be studied.
• Sample : This is a part or a subset that is found in the population.
• Character : these are the characteristics or aspects that need to be studied in the population.
• Random phenomena : are the experiments that give different results but under the same conditions.
• Deterministic phenomena : are those experiments that always give the same result.
• Census : it is the study of all the elements that are part of the population.
• Univariate study : it is the study that is carried out on the characteristics.
• Bivariate study : this term refers to the study of two characteristics.
• Parameter : is the function that is used for the population values.

## Importance of descriptive statistics

Its importance lies in the fact that it is a process through which it is possible to analyze , carry out studies and make descriptions of the individuals that live in a certain population with the sole objective of being able to collect accurate information , to be able to study and analyze this information and to summarize it as much as possible so that its interpretation is easier to carry out. It is also important because of this, it works perfectly as a tool in decision-making , in investigations and because it helps to obtain the minimum degree of error in a given situation.

## Examples

Some examples of descriptive statistics are as follows:

• To carry out a study based on breast cancer in a given place, the individual will be the women who live in the place, the population will be the entire group of women together and the sample will be 1% of the census.
• A study of the height of a group of people in a population yields data indicating that the heights are presented continuously.