Quite often there are phenomena that can be analyzed exclusively using statistical methods. In this regard, for each subject seeking to deeply study the problem, to gain insight into the topic, it is important to have an idea about them. In the article we will understand what a statistical analysis of data is, what are its features, and also what methods are used in its implementation.
Terminology features
Statistics are considered as a specific science, a system of government agencies, as well as a set of numbers. Meanwhile, not all figures can be considered statistics. We will deal with this issue.
To begin with, it should be remembered that the word "statistics" has Latin roots and comes from the concept of status. In a literal translation, the term means "a certain position of objects, things." Consequently, only such data are recognized as statistical with the help of which relatively stable phenomena are recorded. Analysis, in fact, reveals this stability. It is used, for example, in the study of socio-economic, political phenomena.
Appointment
The use of statistical analysis allows you to display quantitative indicators inextricably linked with qualitative. As a result, the researcher can see the interaction of facts, establish patterns, identify typical signs of situations, development scenarios, substantiate the forecast.
Statistical analysis is one of the key media tools. Most often it is used in business publications, such as, for example, Vedomosti, Kommersant, Expert Profi, etc. They always publish "analytical considerations" about the exchange rate, stock quotes, discount rates, investments, the market , the economy as a whole.
Of course, to ensure that the results of the analysis are reliable, data is constantly being collected.
Sources of information
Data collection can be done in different ways. The main thing is that the methods do not violate the law and do not infringe on the interests of others. If we talk about the media, then for them the key sources of information are the state statistical authorities. These structures should:
- Collect reporting information in accordance with approved programs.
- Group information according to certain criteria that are most significant for the phenomenon being studied, and generate summaries.
- Conduct your own statistical analysis.
The tasks of authorized state bodies also include the provision of the data they received in reports, collections or press releases. Recently, statistics are published on the official websites of government agencies.
In addition to these bodies, information can be obtained in the Unified State Register of enterprises, institutions, associations and organizations. The purpose of its creation is to form a single information base.
For the analysis, you can use the information received from intergovernmental organizations. There are special databases of economic statistics of countries.
Often information comes from private individuals, public organizations. These subjects usually keep their statistics. So, for example, the Union for the Protection of Birds in Russia regularly organizes the so-called nightingale evenings. At the end of May, through the media, the organization invites everyone to participate in the calculation of nightingales in Moscow. The information received is processed by a group of experts. After that, the information is transferred to a special card.
Many journalists seek information from representatives of other reputable media outlets that are popular with the audience. A common way to obtain data is to survey. At the same time, both ordinary citizens and experts in any field can become interviewed.
The specifics of the choice of methodology
The list of indicators necessary for the analysis depends on the specifics of the phenomenon being studied. For example, if we study the level of well-being of the population, priority is given to data on the quality of life of citizens, the minimum subsistence level in a given territory, the minimum wage, pension, scholarship, and consumer basket. In the study of the demographic situation, mortality and birth rates and the number of migrants are important. If the field of industrial production is being studied, important information for statistical analysis is the number of enterprises, their types, volume of production, level of labor productivity, etc.
Average performance
As a rule, when describing certain phenomena, arithmetic means are used. To get them, the numbers are added together, and the result is divided by their number.
Average values are used as general indicators. However, they do not allow us to describe specific points. For example, the analysis found that the average salary in Russia is 30 thousand rubles. This indicator does not mean that all working citizens of the country receive exactly this amount. Moreover, someone may have a higher salary, while someone may have a lower salary.
Relative indicators
They are found as a result of a comparative analysis. In statistics, in addition to average, absolute values are used. When comparing them, relative indicators are determined .
For example, it has been established that 5,000 letters are sent to one state agency every month, and 1,000 to another. It turns out that the first structure receives 5 times more calls. When comparing average indicators, the relative value can be expressed as a percentage. For example, the average earnings of a pharmacist is 70% of cf. s / n engineer.
Summary reports
They represent a systematization of the features of the investigated event to identify the dynamics of its development. For example, it was found that in 1997 the river transport of all departments and departments transported 52.4 million tons of cargo, and in 2007 - 101.2 million tons. In order to understand the changes in the nature of transportation for the period from 1997 to 2007, You can group totals by type of object, and then compare the groups with each other. As a result, you can get more complete information about the development of cargo turnover.
Indices
They are widely used in the study of the dynamics of events. The index in statistical analysis is an average indicator reflecting a change in a phenomenon under the influence of another event, the absolute indicators of which are recognized unchanged.
For example, in demography, the value of the natural decline (growth) of the population can act as a specific index. It is determined by comparing fertility and mortality.
Graphs
They are used to display the dynamics of an event. To do this, use figures, points, lines with arbitrary values. Graphs with the help of which quantitative relations are expressed are called diagrams or dynamic curves. Thanks to them, you can clearly see the dynamics of the development of a phenomenon.
The graph showing the increase in the number of people with osteochondrosis is a curve going up. Accordingly, on it you can clearly see the trend in incidence. People, without even reading the text material, can formulate conclusions about the current dynamics and predict the development of the situation in the future.
Statistical Tables
They are very often used to reflect data. Using statistical tables, you can compare information on indicators that change over time, varying by country, etc. They are visual statistics that often do not need comments.
Methods
The statistical analysis is based on techniques and methods for collecting, processing and summarizing information. Depending on the nature of the methods can be quantitative and categorical.
Using the first, they obtain metric data, which in their structure are continuous. They can be measured using the interval scale. It is a system of numbers, equal intervals between which reflect the periodicity of the values of the studied indicators. A relationship scale is also used. In it, in addition to distance, the order of values is also determined.
Non-metric (categorical) data is qualitative information, the number of unique categories and values of which is limited. They can be presented in the form of nominal or ordinal indicators. The former are used to number objects. For the second, a natural order is provided.
One-dimensional methods
They are used if a single meter is used to evaluate all the elements of the sample, or if there are several of them for each component, but the variables are examined separately from each other.
One-dimensional methods differ depending on the type of data: metric or non-metric. The former are measured on a relative or interval scale, the latter on a nominal or ordinal scale. In addition, methods are divided into classes depending on the number of samples studied. It should be borne in mind that this number is determined by how the work with information for a specific analysis is carried out, and not by the method of data collection.
One-way ANOVA
The purpose of statistical analysis may be to study the effect of one or more factors on a particular feature of an object. The one-way dispersion method is used when the researcher has 3 or more independent samples. Moreover, they should be obtained from the general population by changing the independent factor, for which there are no quantitative measurements for some reason. It is assumed that there are different and the same sample variances. In this regard, it should be determined whether this factor had a significant impact on the spread or whether it was a consequence of accidents arising from small sample sizes.
Variation series
It is an ordered distribution of units of the general population, as a rule, according to increasing (in rare cases, decreasing) indicators of a characteristic and counting their number with one or another value of the characteristic.
Variation is the difference in the indicator of a trait in different units of a particular population that occurs at the same time or period. For example, company employees differ from each other in age, growth, income, weight, etc. There is a variation due to the fact that individual characteristics of the attribute are formed under the complex influence of various factors. In each case, they are combined in different ways.
The variation series is:
- Ranked. It is presented in the form of a list of individual units of the general population, arranged in descending or increasing order of the investigated trait.
- Discrete. It is presented in the form of a table that includes specific indicators of the changing feature x and the number of units of the population with a given value f of the characteristic of frequencies.
- Interval. In this case, the indicator of a continuous attribute is set using intervals. They are characterized by a frequency t.
Multivariate Statistical Analysis
It is carried out if 2 or more meters are used to evaluate the elements of the sample, and the variables are studied simultaneously. This form of statistical analysis differs from the one-dimensional method in the first place in that when it is used, attention focuses on the level of the relationship between phenomena, and not on average indicators and distributions (variances).
Among the main methods of multivariate statistical research, there are:
- Cross Tab With its use, the value of two or more variables is simultaneously characterized.
- Dispersion statistical analysis. This method is aimed at finding dependencies among experimental data by studying the significance of differences in average indicators.
- Covariance analysis. It is closely related to the dispersion method. In a covariance study, the dependent variable is adjusted in accordance with the information associated with it. This provides the opportunity to eliminate the variability introduced from the outside, and, accordingly, increase the effectiveness of the study.
There is also discriminant analysis. It is used if the dependent variable is categorical and the independent (predictors) are interval.