The statistics Is a branch of mathematics, which corresponds to the collection, analysis, interpretation, presentation and organization of data (set of values of qualitative or quantitative variable). This discipline seeks to explain the relationships and dependencies of a phenomenon (physical or natural).
Statistician and English economist Arthur Lyon Bowley, defines statistics as:"Numerical statements of fact from any research department, in relation to one another." In this sense, statistics are responsible for studying a particular population (In statistics, set of individuals, objects or phenomena) and / or mass or collective phenomena.
This branch of mathematics is a transverse science, that is, applicable to a variety of disciplines, ranging from physics to social sciences, health sciences or quality control.
In addition, it has great value in business or government activities, where the study of the data obtained makes it easier to make decisions or make generalizations.
A common practice to perform a statistical study applied to a problem is to start by determining a population , Which can be of various subjects.
A common example of population is the total population of a country, so when conducting a national population census, a statistical study is being done.
Some specialized disciplines of statistics are: actuarial sciences, biostatistics, demography, industrial statistics, statistical physics, surveys, statistics in the social sciences, econometrics, etc.
In psychology, the discipline of psychometry , Which specializes in and quantifies psychological variables specific to the human mind, using statistical procedures.
Major Branches of Statistics
The statistic is divided into two major areas: Descriptive statistics And E Inferential statistics , Which comprise the E applied Statistics .
In addition to these two areas, there is Mathematical statistics , Which comprise the theoretical bases of statistics.
1- Descriptive Statistics
The Descriptive statistics Is the branch of statistics that describes or summarizes quantitatively (characteristics) a collection of a collection of information.
That is, descriptive statistics is responsible for summarizing a statistical sample (set of data obtained from a population ) Rather than learning about population Which represents the sample.
Some of the measures commonly used in descriptive statistics to describe a set of data are the measures of central tendency and the Measures of variability or dispersion .
As for measures of central tendency, measures such as half , the median and the fashion . While in the measures of variability the Variance , the Kurtosis , etc.
Descriptive statistics is usually the first part to be performed in a statistical analysis. The results of these studies are usually accompanied by graphs, and represent the basis of almost any quantitative (measurable) analysis of data.
An example of descriptive statistics might be to consider a number to summarize how well a baseball batter is performing.
Thus, the number is obtained by the number of Hits Which has given a batter divided by the number of times he has been at bat. However, this study will not give more specific information, such as which of those batters have been Home Runs.
Other examples of descriptive statistics studies may be: The average age of citizens living in a certain geographic area, the average length of all books pertaining to a specific subject, the variation with respect to the time visitors spend navigating in one Internet page.
2- Inferential Statistics
The Inferential statistics Is distinguished from descriptive statistics mainly by the use of inference and induction.
That is, this branch of statistics seeks to deduce properties from a population Studied, that is, not only collects and summarizes the data, but also seeks to explain certain properties or characteristics from the data obtained.
In this sense, inferential statistics implies obtaining the correct conclusions from a statistical analysis performed using descriptive statistics.
For this reason, many of the experiments in social sciences involve a group of population As well as inferences and generalizations can be determined as the population In general behaves.
The conclusions obtained by inferential statistics are subject to randomness (absence of patterns or regularities) but by the application of the appropriate methods it is possible to obtain relevant results.
Thus, both the Descriptive statistics as the Inferential statistics They go hand in hand.
Inferential statistics are divided into:
Parametric Statistics
It comprises the statistical procedures based on the distribution of the actual data, which are determined by a finite number of parameters (number that summarizes the amount of data derived from a statistical variable).
In order to apply parametric procedures, it is necessary to know in advance the form of distribution for the resulting forms of the studied population.
Therefore, if the distribution of the data obtained is unknown, a non-parametric procedure should be used.
Non-parametric statistics
This branch of inferential statistics comprises procedures applied in tests and statistical models in which their distribution does not fit the so-called parametric criteria. As the data studied are those that define its distribution, it can not be defined previously.
Nonparametric statistics is the procedure that must be chosen by not knowing if the data fit a known distribution, so that it can be a step before the parametric procedure.
Likewise, in a non-parametric test, the error possibilities are reduced by the use of suitable sample sizes.
Mathematical Statistics
It has also been mentioned the existence of the Mathematical Statistics , As a discipline of statistics.
This consists of a previous scale in the study of statistics, in which they use the theory of probability (branch of mathematics that studies the Random phenomena ) And other branches of mathematics.
Mathematical statistics consists of obtaining information from the data and uses mathematical techniques such as: Mathematical analysis, linear algebra, stochastic analysis, differential equations, etc. Thus, mathematical statistics has been influenced by applied statistics.
References
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- Parametric statistics. (2017, 10 February). Wikipedia, the free encyclopedia . Date of consultation: 08:30, July 4, 2017 from es.wikipedia.org
- Non-parametric statistics. (2015, August 14). Wikipedia, the free encyclopedia . Date of consultation: 08:30, July 4, 2017 from es.wikipedia.org
- Descriptive statistics. (2017, June 29). Wikipedia, the free encyclopedia . Date of consultation: 08:30, July 4, 2017 from es.wikipedia.org
- Inferential statistics. (2017, May 24). Wikipedia, the free encyclopedia . Date of consultation: 08:30, July 4, 2017 from es.wikipedia.org
- Statistical inference. (2017, July 1). In Wikipedia, The Free Encyclopedia . Retrieved 08:30, July 4, 2017, from en.wikipedia.org
- Inferential Statistics (2006, october 20). In Research Methods Knowledge Base. Retrieved 08:31, July 4, 2017, from socialresearchmethods.net
- Descriptive Statistics (2006, october 20). In Research Methods Knowledge Base. Retrieved 08:31, July 4, 2017, from socialresearchmethods.net.