## Definition, concept, meaning, what is Variable

### 1. Concept of Variable

You can define as everything that is going to measure, control and study in a research or study. The ability to measure, control or study a variable is given by the fact that it varies, and this variation can observe, measure, and study. It is therefore important, before initiating an investigation, that you know what are the variables that you want to measure and the way in which it will be. I.e., the variables must be measurable. Thus a variable v is everything that can assume different values, since the quantitative or qualitative point of view. Variables can be defined conceptually and operationally.
The conceptual definition is theoretical in nature, while the operational bases of measurement and definition of indicators.

There are three types of variables, dependent, independent, and intervening variable.

#### The dependent variable.

It is the object or event of study, on which research is focused in general.
For example: pollutants from the Valencia Lake.

It can also be defined as the changes suffered by individuals as a result of the manipulation of the independent variable by the experimenter. In this case the name says so explicitly, it will depend on what makes it vary.

For example: as influences classical music in the growth of the tomatoes.

In this case the dependent variable would be "growth of tomatoes" as a result of the manipulation of the independent variable "classical music". So you must take note that always the dependent variable should appear as it is in the title of a work is the object of study.

#### The independent variable.

It is the property of a phenomenon that are going to evaluate his ability to affect, influence or affect other variables. Best mode on the fact that explains its name of does not depend on 'something' to 'be there' as it is the case of the sex of a subject, or music in the previous example. There are, however, independent variables in some studies that in some measure depend on 'something', as the economic entrance of a school may depend on the Ministry of education, but the object of study is not impacting on the independent variable. Thus a study independent variable is believed that it is influencing the dependent variable, Correlacional study focuses precisely on that relationship.

Some independent variables such as sex, socioeconomic level are variables that the researcher cannot be changed, are not manipulated. However, you want to know whether it influences the dependent variable. This is called independent variable assigned or selected, while the independent variable by manipulation is that the researcher applies in its sole discretion, is in experimental studies. Everything that the researcher manipulates, since it believes that there is a relationship between this and the dependent variable.
Intervening variable and variable intra.
The variable inter are those who study simultaneously several groups of subjects. The comparisons are established between (inter) groups.

The variable intra are those that can study the same group at different times. That is, comparisons are set within a same group.

#### Foreign variables

They are all those variables that the researcher does not control directly, but that they can influence the outcome of their investigation. They should be controlled, as much as possible, to ensure that the results are due to management that the researcher made of the independent variable, not to strange, uncontrolled variables. This can be done more easily under an experimental, as within a controlled environment, laboratory research. In a quasi-experimental research with subjects such as people, becomes a little more difficult. Some methods to carry out this control are as follows:

#### Elimination:

When you know that there is a strange variable that may alter the results of the research, it can be controlled by removing.

#### Constancy of conditions:

If, for example, in a pilot study you want to study two or more groups of subjects or samples, they should have exactly the same conditions, physical and as of place, maintaining, in this way, constant circumstances under which is investigated.

#### Balance:

When you know that a variable strange can permanently influencing the study and not be deleted, or match the conditions of samples or groups, are used to rolling. This mechanism distributed in an equitable manner the presence of the variable odd between the groups.

#### I counterbalance:

Some research calls to subjects or sample to respond several times to a same stimulus or to several different stimuli. This series of responses can result in the same two reactions: on the one hand, fatigue, because subjects are tired of be responding; on the other hand, learning, since after 2 or 3 times the same stimulus the subject already knows how to respond. To avoid these problems, the groups can be subdivided into sub-groups so that the effects of fatigue and/or learning are cancelled.

#### Randomization:

This method of control is one of the simplest and most commonly used in the social sciences, especially when experimental studies are conducted. Part of the premise of that whether the selection and distribution of subjects in control groups was done randomly, it can be inferred that strange variables, unknown by the investigator, will also be distributed randomly in both groups, and thus will be matched. Similarly, you can pass in some experiments in life sciences.

#### Causality

Speaking of independent and dependent variables, be careful not to fall into the trap of stating that the dependent variable is caused by the independent variable. This kind of conclusions you can be reached in very limited situations. In social sciences, it is convenient to speak of relations among variables, and not causes. In this way, we can say that the dependent variable, as its name indicates it will depend on "something" that can vary. Elements, phenomena and mechanisms that can be made to vary the dependent variable are the independent variables. Studies in exploratory and descriptive or qualitative, the dependent variables are studied to identify possible elements (independent variable) can be involved in the event or phenomenon that do vary the object of study, the dependent variable.

### 2. Meaning of Variable

OPERATIONALIZATION OF VARIABLES

The variable term is defined as characteristics or attributes that support different values (D´Ary, Jacobs, and Razavieh, 1982) as for example, height, age, IQ, temperature, climate, etc. There are many forms of classification of the variables, however, this section shall be classified according to the subject of study and the use of this site.

According to the subject of research variables are classified in continuous and categorical. Categorical variables classified subjects by distributing them in groups, according to a previously established attribute, for example, language, occupation, etc. This type of variables are subdivided in turn into two: dichotomous variables that have two categories for example between men and women, and variable policotomicas laying down three or more categories, for example marital status, academic level, etc. They are continuous variables are measured attributes that take an infinite number of values, such as for example, weight, size, height, etc.

THE OPERATIONALIZATION OF VARIABLES

It is a process that begins with the definition of the variables on the basis of strictly measurable factors which are called indicators.

The process requires to perform a conceptual definition of the variables to break the diffuse concept that it encompasses and give concrete sense within the research, then in function of this process to perform the operational definition of the same to identify indicators that will allow measurement of empirical and quantitative, way to qualitatively if necessary.

WHAT ARE VARIABLES?

At this point, it is necessary to define what is a variable. A variable is a property that can vary and whose variation is likely to be measured or observed. Example of variables: sex, intrinsic work motivation, physical attractiveness, learning concepts, historical knowledge on the integration efforts of Simón Bolívar, religion, resistance of a natural, verbal aggression, the authoritarian personality, the tax culture and exposure to a political propaganda campaign. The variable applies to a group of people or objects, which take on different values or statements with respect to the variable. For example, intelligence: it is possible to classify people according to their intelligence, vary it.

Other variables are the productivity of a particular type of seed, the speed with which offered service, the efficiency of a construction procedure, the effectiveness of a vaccine, the time that it takes to manifest itself a disease, etc (there is variation in all cases).

CONCEPTUAL definition: Basically, the conceptual definition of the
variables is an abstraction articulated in words to facilitate their understanding and their suitability to the practical requirements of the research.

OPERATIONAL definition: An operational definition consists of a set of instructions or procedures for the measurement of a variable defined conceptually. The operational definition should be considered that what is attempted is the additional information of the selected variable, so that it captures its sense and fits the context, and for this purpose should be a careful review of the available literature on the subject of research.

The operationalization of variables is closely linked to the type of technique or methodology employed for data collection. These should be consistent with the objectives of the research, and to respond to the approach, to the type of research that is carried out. These techniques, in General, may be qualitative or quantitative.

VARIABLES, dimensions and indicators: When faced with complex variables, where the passage of the conceptual definition to its implementation requires intermediate instances, then can be a distinction between variables, dimensions and indicators. To sum, it can be said that the passage of the dimension to the indicator makes a journey from the general to the particular, from the plane of the theoretical to the plane of the empirically verifiable.

The dimensions would be subvariables or variable with a level closer to the indicator. In the case of defining a variable productivity, we have different sub-dimensions which are part of the variable, such as: labour, machinery, material or energy. Each of these subvariables are the dimensions of the variable productivity.

In turn, these dimensions, to be able to be empirically contrasted by the researcher, require operationalization in indicators, which are nothing other than parameters contributing to situation in which is located the problem to study. In a narrow sense, the indicators are data.

For variable productivity, for example, in the labour dimension, indicators could be number of products packaged by one worker in eight hours of work.

OPERATIONALIZATION OF VARIABLES

Variable: Any feature of reality that can be determined by observation and that can show different values of an observation unit to another.

Variable: Is an aspect or dimension of a phenomenon that features the ability to assume different values, either quantitative or qualitative.

The validity of a variable depends on systematically the theoretical framework that he based the problem and which has collapsed, and its direct relationship with the hypothesis (or idea to defend) that supports it.

In the process of operationalization of some variables, it is necessary to determine the measurement parameters from which the relationship of variables contained by the hypothesis (or idea to defend), will be established for which it is necessary to take into account:

• The statement of the hypothesis (or idea to defend) must be backed by a fact or problem.
• Reality or problematic situation: children of mothers from early pregnancy, presented in their preschool-age children difficult in the ability to learn to read.
• In the operationalization of variables is necessary to take into account two important factors:
• The logic
• Knowledge: is necessary the relevant Reformation, which enables to build dimensions and indicators.
• The minimum information necessary for analysis in a research comes from the operationalization of variables, since the relationship of the data collection instruments are constructed from dimensions and indicators of the variable.

CLASSIFICATION OF VARIABLES

According to your ability or level that allow us to measure objects. In other words, the most common and basic of a variables feature is the differentiate between the presence and the absence of the property which it enunciates.

Continuous variable: occurs when the phenomenon to be measured can take quantitatively different values. Examples: the chronological age.

Discrete variables: are those established categories not quantitatively between different individuals or elements. Example: the temperament of children in relation to learning - children of calm temperament learn more slowly than of temperament.

Individual variables: they present the feature or property which characterizes certain individuals, and they can be: absolute. Relational. Comparative. Contextual.

Collective variables: present the characteristics or properties that distinguish a group or collective determined and can be: analytical. Structural. Global.

Antecedent variable: It is which is supposed as background, i.e., that there are variables which are a history of others. Example: to make learning it is a minimal degree of intelligence. Therefore, the variable intelligence is an antecedent of the variable learning.

Independent variable: it is the variable that precedes a dependent variable, which is presented as the cause and condition of the dependent variable, i.e., are conditions that are manipulated by the researcher in order to produce certain effects.

Dependent variable: variable that occurs as a result of an antecedent variable. That is, it's the effect of the variable which is considered independent, which is managed by the researcher.

Variable intervening or AC: is the variable that appears is interposing between the independent variable and the dependent variable and at the time of interacting variables involved significantly.

It is important to analyze whether this variable appears from the independent variable, i.e., posterior to it and prior to the dependent variable, so that you enter to replace the independent variable that has been formulated, or its acts as a relative factor in the relationship of variables.

Strange variables: when there is an independent variable not related to the purpose of the study, but that may have effects on the dependent variable, we have a strange variable.

### 3. Definition of Variable

The variable term is used when you want to mean that some things, situations and it even if people have a recurrence to the instability and inconstancy. This broadly and very informally of course, but if we get a little more serious and formal, say that variable is what we said and in addition is a symbol that represents an item not specified or identified from a given set. This same set is called a universal set of variable and each Member of that group is a value of the variable.
For example, and in order to make it more clear, 'X' is a variable of the next universe 2, 4, 6, 8, whereby x will have any of those values and may be replaced by any less than 9 par value.
In this case and as we saw through the example, the variable is an element of a formula that can be replaced or purchase any value within that universe; out of it, obviously, this is impossible. Meanwhile, there are different types of variables, we have subsidiaries and independents on one side and on the other with the qualitative and quantitative. The first are which will depend on the value that assume the other variables and the latter are those that may experience changes per is in its value and affect the other. For example, in a model in which the price of an object is a weight, the number of objects that I consider is an independent variable, while the final price, to link up directly with the amount of objects, will be the dependent variable. In this simple variant, the independent variable "four objects" you is the dependent variable "four pesos".
On the other hand, qualitative variables express qualities, characteristics, or different modes and the quantitative are set out only in numbers. Thus, as different parameters such as price, blood pressure, the number of legs of an animal or the number of parts of a motor are quantitative variables. On the other hand, hair color, marks of automotive dealership, the authors present in a library or a local stock components are qualitative variables. In this regard, it is interesting to note a special type of qualitative variable, which is called a dichotomous variable: "Yes" or "no", only 2 possible options. When you want to analyze with statistical techniques some varying more or less complex, a widely used strategy is to replace a dichotomous variable by a numeric code; "Yes" becomes in "1″ and"no"is converted to"0″. " This trick has expanded so that, when we stumbled upon qualitative variables with more than two possible options, it is possible your numeric data conversion and, in that way, be able to extract information. The best example is the replacement of the months of the year by its order in the calendar: "January" (qualitative variable) is "1″ (numeric variable)... and thus to"December"which becomes"12″. "
Through the analysis of variables have been made numerous advances in human knowledge areas as diverse as mathematics, economics, geology, archaeology, and the health sciences. Therefore, the knowledge of these "companions of route" of every day makes it easy to understand better the world that surrounds us.