Types of variables in the experiment. Independent variable Which variable is dependent which independent

Independent variables - these are the means that are available to the experimenter to influence the subjects.

Dependent variable - these are the changes that occur in the state, behavior, communication and activities of the subjects under the influence of the experimenter.

External variables (noise) - those factors (conditions) that also affect the subjects in addition to the will of the experimenter (fatigue, noise outside the window).

The experimenter should strive to reduce the impact of external variables on the subjects.

Independent variables

Quality - are expressed in the fact that any effect is either present in the experiment or absent.

(For example: experimenter's prompt (maybe, maybe not)).

quantitative - is expressed in various degrees (more than two) of the influence of the experimenter on the subjects.

Independent variables may take the following forms:

Show up in:

In job elements;

In the elements of the experimental situation;

In the characteristics of the state of the subject.

In the task, the experimenter varies:

1. Characteristics of impact (strong, weak impact).

2. The material of the task (written, on the computer).

3. The type of response of the subject (verbal and non-verbal).

4. Evaluation scale (money).

5. Instruction (may change, but should not).

6. The purpose and action of the subject.

7. Means that the subject has.

8. Obstacles that are placed on him.

9. The system of rewards and punishments for the subjects.

In the situation, they will:

1. Physical parameters:

Equipment location;

The appearance of the premises;

illumination;

Sounds and noises;

temperature;

Placement of furniture;

Experiment behavior time

How long;
Times of Day.

2. Socio-psychological parameters:

Work in the presence of the experimenter;

Either work in isolation;

In a group;

Or when communicating with the experimenter.

3. Features of the state of the subject:

Mental stress;

The level of experienced stress, fear, frustration: the level of conformity;

Rivalry, etc.

Types of dependent variables

(what the experimenter manipulates)

One-dimensional – only one parameter is registered. It is he who is considered a manifestation of the dependent variable. (Reaction time)

Multidimensional - a number of parameters are selected that are fixed. (For example: problem solving time, solution quality, originality, etc.).

Fundamental .

Dependent variable is considered as a function of individual parameters of its manifestation. (For example: aggressiveness level – is considered as a function of the interaction of the following parameters:

verbal aggression;

non-verbal aggression;

Indirect aggression (loudly slammed the door);

The manifestation of irritability, etc.

, where a - parameter.

According to this principle, the level of aggression is determined. Questionnaire for the definition of aggressiveness.

The change in the dependent variable is determined by the change in the parameters of the subject's behavior. They are conventionally divided into formal dynamic and meaningful .

To formal dynamic include:

Task accuracy

Latency (i.e. latent time from the moment the signal is presented to the choice of the answer).

Execution time

Pace or frequency of action

Productivity – i.e. the ratio of the result obtained to the execution time.

extrapunity – external accusatory behavior (S. Rosenzweig)

intropunity - self-blame.

Immunity – no one blames, but tries to understand the situation.

Dependent variable must be valid (degree of conformity), reliable and sensitive.

Validity – the degree of compliance of the dependent variable with the hypothesis.

Dependent Variable Reliability - means that the level of manifestation of the dependent variable is steadily fixed during the experiment.

Sensitivity - talks about how much the dependent variable changes when the independent variable changes.

There are 2 variants of manifestation of the type of insensitivity of the dependent variable:

ceiling effect - manifests itself in the fact that the task is so simple that the level of its performance by the subject is higher than all levels of the independent variable. (For example: multiplication table).

floor effect - on the contrary, it occurs when the simplest level of the independent variable is so difficult for the subject that he is not able to perform it.

Dependent Variable Changes manifested in a change in the state of a person, communication, behavior, activity, facial expressions, posture, activity, emotionality, etc.

In order to find out its effect on the dependent variable.

Dependent variable- in a scientific experiment, a measured variable, changes in which are associated with changes in the independent variable.

The independent variable, for example, in a psychological experiment, can be considered the intensity of the stimulus, and the dependent variable is the ability of the subject to feel this stimulus.

Types of relationship between variables

The dependent variable is not sensitive to changes in the independent variable.
Monotonically increasing dependence: an increase in the values of the independent variable corresponds to a change in the dependent variable.
Monotonically decreasing dependence: an increase in the values of the independent variable corresponds to a decrease in the level of the independent variable.
Non-linear dependence of the U-shaped type - found in most experiments in which features of the mental regulation of behavior are highlighted
Inverted U-shaped dependence - obtained in numerous experiments and correlation studies.
Complex quasi-periodic dependence of the level of the dependent variable on the level of the independent.

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See what "Independent variable" is in other dictionaries:

Independent variable- Some aspect of the experimental situation that is under the direct control of the experimenter, who observes its possible influence on the behavior of the participants (see Dependent variable). For example, dividing participants into groups that are given ... ... Great Psychological Encyclopedia

INDEPENDENT VARIABLE, see VARIABLE... Scientific and technical encyclopedic dictionary

Independent variable- - see Function Argument... Economic and Mathematical Dictionary

independent variable- — [Ya.N. Luginsky, M.S. Fezi Zhilinskaya, Yu.S. Kabirov. English Russian Dictionary of Electrical Engineering and Power Industry, Moscow, 1999] Electrical engineering topics, basic concepts EN independent variable ... Technical Translator's Handbook

Independent variable- (independent variabile) - a variable that is controlled experimentally or for the purpose of observing its impact on other, dependent variables. For example, the speed limit on the roads is an independent variable, and the number ... ... Encyclopedic Dictionary of Psychology and Pedagogy

INDEPENDENT VARIABLE- (independent variable) a variable that is controlled experimentally or for the purpose of observing its impact. For example, some roads may systematically limit the speed of traffic, and the effect is measured in terms of statistics ... ... Big explanatory sociological dictionary

independent variable- nepriklausomasis kintamasis statusas T sritis automatika atitikmenys: engl. independent variable vok. unabhangige variable, f rus. independent variable, fpranc. grandeur indépendante, f … Automatikos terminų žodynas

independent variable- nepriklausomasis kintamasis statusas T sritis fizika atitikmenys: engl. independent variable vok. unabhängige Veränderliche, f rus. independent variable, fpranc. variable independante, f … Fizikos terminų žodynas

independent variable- Variable used to predict values, explanation, dependent variable. Synonyms: predictor, explanatory variable. See also dependent variable... Dictionary of Sociological Statistics

Independent variable- - a variable that causes a change in another (dependent) variable ... Social Work Dictionary

variable any measurable characteristic that can have more than one value is called. Examples of variables are gender (female and male), height, political affiliation (Republican, Democrat, Communist, etc.), habits of predominantly using one hand (right-handed, left-handed, wielding both hands equally), and attitudes towards traditional gender roles (maybe range from extremely negative to extremely positive). When testing hypotheses, we start by choosing the variables we are interested in.

In the story that begins this chapter, you were asked to determine which of two treatment programs were more likely to help you break your heroin addiction. In this example, two variables are the type of treatment, which is independent variable, i.e. you can choose it (program 1 or program 2) and the cure which is dependent variable, i.e. you think that this variable changes depending on the type of treatment you will either a) recover from addiction or b) not recover from addiction. You want to choose a program that will help you heal. In hypothesis testing terminology, you want to know what value of the independent variable will favorably affect the dependent variable.

The next step in the hypothesis testing process is the introduction of working variable definitions. Suppose we decide to define "recovered" as being abstinent from drugs for at least two years, and "not cured" as being abstinent from drugs for a period of less than two years, which includes if you continue to use drugs continuously. It is important to think critically about the working definitions of your variables. If they are not formulated satisfactorily, then the conclusion that you will come to as a result of your research may be wrong.

Measurement sensitivity

When measuring a quantity, we constantly give it numerical values in order to obtain its quantitative characteristics. The height of a person who is taller than you is indicated by a greater number of inches than your height. Otherwise, the concept of growth would lose its meaning.

When we think like scientists and gather information to understand how the world works, we need to consider how variables are measured. Suppose you think that love is like a fever and that lovers have symptoms that are like symptoms of a fever. To find out if this is true, you can experiment by taking the temperature of people who are in love and comparing the results with those of people who are not in love. How will you measure the temperature? Let's say you decide to use a tape thermometer that records the temperature when it is placed on the patient's forehead. Further suppose that this instrument measures temperature by rounding it to whole degrees (for example, 36°, 37°, 38°, etc.). If the body temperature really rises from love, but only by half a degree, you will never know this using a tape thermometer. Such thermometers are simply not sensitive enough to register small variations in body temperature. You will come to the wrong conclusion that love does not lead to an increase in body temperature, when in fact this may not be the case. As far as I know, such an experiment has never been performed, but it well demonstrates the need to take into account the sensitivity of measurements in this and other situations.

Plan:

1. Independent variable.

2. Dependent variable.

3. Control of variables.

Variables is a parameter of reality that may or may not change in an experimental study. There are:

Independent variables - changed by the experimenter;

Dependent variables - change under the influence of changes in the independent variable;

External - inaccessible to control, but affecting the dependent variable, the source of error;

Latent - inaccessible to direct measurement, are fixed by analyzing the joint variations of dependent variables;

Additional - external variables taken into account in the experiment.

Independent variable

A pure experiment involves operating only the independent variable. Therefore, when conducting an experimental study, it is necessary to isolate the independent variable and isolate it from others.

The independent variables can be:

1 - features of the tasks proposed for completion (material, instructions, obstacles to achieving the goal, etc.);

2 - characteristics of the situation (air temperature in the room, noise in the shop, loud music, interior, etc.);

3 - controlled states of the subject (personal qualities, professional skills, mental characteristics);

4 - constant characteristics of the subject (gender, age, work experience, intelligence level, status, etc.).

In relation to the dependent variable, the independent variable can enter into the following dependencies:

1. No dependency. Changing the independent variable does not change the dependent variable in any way.

2. Monotonically increasing dependence. Increasing the value of the independent variable increases the value of the dependent variable.

3. Monotonically decreasing dependence. An increase in the values of the independent variable corresponds to a decrease in the values of the dependent variable.

4. Nonlinear dependence. High values of the independent variable can correspond to both high and low values of the dependent variable.

Dependent variable

The dependent variable is always changed by a change in the independent variable or under its influence.

The dependent variable should be:

1. Reliable . The reliability of a variable is manifested in the stability of its recordability under changes in experimental conditions over time.

2. Valid. The validity of the dependent variable is determined only under specific experimental conditions and in relation to the relative hypothesis.

3. Sensitive . Sensitivity (sensitivity) is manifested in the possibility of changing the variable when manipulating the independent variable.

There are three types of dependent variables:

Simultaneous: only one parameter is recorded, and it is this parameter that is considered to be the manifestation of the dependent variable.

Multivariate: The dependent variable appears in multiple parameters.

Fundamental : when the relationship between the individual parameters of a multivariate dependent variable is known, the parameters are considered as arguments and the dependent variable itself as a function.

Variable control

During the experiment, independent and external (side and additional) variables are controlled.

The control of an independent variable consists in its active variation or knowledge of the patterns of its change.

There are two ways to control the independent variable:

If an experiment is conducted, then the control of the independent variable is carried out with the help of active manipulation, variation (during the experiment on the formation of the motivation of the independent variable, there will be conditions - a, c, c - for the formation of motivation. Their presentation / non-presentation is the way to vary the independent variable);

During observation and measurement, control is carried out by selecting the required values from among the already existing variables (for example, a group of subjects is divided into hard of hearing, average hearing and hard of hearing).

External variables are controlled in the following ways:

Elimination of external variables;

Constancy of conditions;

Balancing;

counterbalancing;

Randomization.

Elimination. One of the reliable ways to control external variables An experimental situation is designed in such a way as to exclude the presence of all external variables from it.

Creating constant conditions. If external variables cannot be excluded from the experimental situation, then it is necessary to make them unchanged. At the same time, the influence of external variables remains unchanged for all subjects.

The following should be made unchanged:

Spatio-temporal conditions of the experiment (at the same time of the day, week for all subjects);

Technique and equipment of the premises;

Presentation of instructions.

Balancing. In cases where it is not possible to create constant conditions for conducting an experiment or the constancy of conditions is not enough, the technique of balancing the effect of external variables is used. By design, balancing is applied in situations where the external variable cannot be identified.

The balancing method is as follows: a control group is added to the experimental group (this can be done if the study is experimental). The legitimacy of the hypothesis in this case will be reflected by the presence of results after exposure in the experimental group and their absence in the control group.

The control group is created for each external variable in such a way that in the second group there is no effect on the dependent variable of the external variable that affects the first control group, and so on.

counterbalancing. Acceptance of control of experiments, including several series or sequential tasks. The meaning of counterbalancing is as follows: the order in which tasks, stimuli, tasks, and influences are presented in one of the groups is compensated by a different order in which they are presented in the other.

Randomization. A method that allows to exclude the influence of the individual characteristics of the subjects on the results of the study. It is used in two cases: 1 - it is known how to control external variables, but it is not possible to use any of the previous techniques; 2 - external variables are not identified, are latent or non-specific for this experiment.

Topic. Scientific research planning

Lecture 1. Experimental plans

Plan:

1. Pre-experimental plans.

2. Plans for one independent variable.

3. Factor plans.

Pre-experimental plans

Plan with preliminary and final testing of one group. A plan with preliminary and final testing of one group is often used in sociological, socio-psychological and pedagogical research.

The plan is implemented in three stages: preliminary testing of a sample selected in a certain way - impact (for example, a formative experiment) - repeated testing.

The disadvantages of the plan include the following points. This plan does not control the effect of "natural development"; the effect of testing - the impact of the previous survey on the next one - is another artifact of this plan. In addition, there is no control sample in this plan, so it cannot be argued that changes in the dependent variable recorded during testing are caused precisely by a change in the independent variable. Between the initial and final testing, there are other "background" events that affect the subjects on a par with the independent variable.

Comparison of statistical groups– or a plan for two non-equivalent groups with post-exposure testing.

The experiment is carried out as follows: two spontaneous groups are selected - experimental and control. An experiment is conducted in the experimental group, and it is carried out in the control group. After the experimental exposure, testing is carried out.

The effect of exposure is determined by comparing the test results in both groups.

This plan allows you to control the effect of testing and the influence of background influences and some external variables.

Ex-post-facto plan or the experiment being referenced. The application strategy is as follows: the experimenter himself does not influence the subjects. Some real event from their life acts as an impact (changes in the independent variable). A group of subjects who have been exposed to the effect, and a group that has not experienced it, is selected. The selection is carried out on the basis of data on the characteristics of the subjects before exposure; information can be personal memories and autobiographies, information from archives, personal data, medical records, etc. Then the dependent variable is tested in both groups. The diagnostic data are compared and compared, a conclusion is made about the influence of the “natural” impact on the behavior of the subjects.

This plan is used in many modern studies, for example, in neuropsychology: brain injuries, local lesions, etc.

Designs for one independent variable

Plan for two groups with post-exposure testing(plan R.A. Fisher) Carrying out the plan.

1. Two equivalent groups are selected according to a significant criterion (the variable by which the groups are selected). The equality of the experimental and control groups is achieved most often by randomization.

2. The experimental group is affected, the control group is not.

3. After exposure, both groups are tested for a significant criterion (the same variable for which the groups were selected).

This plan is recommended when there is no need or opportunity for pre-testing. If randomization is carried out qualitatively, then this plan is the best, it allows you to control a large number of artifacts.

The effect of the impact is determined by comparing the results of testing after exposure in the control and experimental groups.

To control external variables, this plan is modified by increasing the number of control groups.

Positive moments of the plans: since there is no preliminary testing, the effect of testing is excluded. The plan allows you to control the influence of the composition of groups, spontaneous dropout, the influence of the background and natural development, the interaction of the composition of groups with other factors. Allows you to eliminate the effect of regression due to randomization and comparison of data from the experimental and control groups.

The negative aspects are the distortion of the results of the selection of subjects according to a significant criterion due to randomization (as a result of the lack of testing).

Plan for two groups with preliminary and final testing (test-impact-retest). One of the popular plans in psychological research.

1. Two groups are selected according to a significant criterion by the appropriate procedure. In both groups, a significant criterion (the variable that will be affected) is tested.

2. In the experimental group there is an effect, in the control group - no.

3. After exposure, repeated testing is carried out in both groups.

The impact effect is determined by:

q comparing the test results of the experimental group at the first and third stages;

q comparing the results of the control group in the first and third stages;

q comparing the test results of the experimental and control groups at the third stage.

The main source of artifacts that violate the external validity of the procedure is the interaction of testing with experimental influence (testing effect)

Plan R.L. Solomon. Solomon's plan is used when conducting an experiment on four groups: two experimental and two control. It is a combination of two previous plans: the first, when there is no preliminary testing, and the second - "test - impact - retest".

The plan is implemented as follows:

1. Using an appropriate procedure (usually randomization), 4 groups are selected (two will be experimental and two will be control).

2. In the first experimental group, preliminary testing, exposure and final testing are carried out.

3. In the first control group, preliminary and final testing is carried out, there is no effect.

4. In the second control group, experimental exposure and testing after exposure is carried out.

5. In the second control group, only repeated testing without exposure is carried out.

The effect of experimental exposure is determined by:

q comparison of test results in the first experimental group at the first and third stages;

q comparison of the results of the final testing in the first experimental and first control groups;

q comparing the results of the final testing in the second experimental and second control groups;

q comparison of the results of final testing in the second experimental group and primary testing in the first control group.

By comparing the final test in the second control group with the results of the pre-test in the first experimental and pre-test in the first control group, it is possible to identify the combined effect of the effect of natural development and background influences on the dependent variable.

Factorial plans

Factorial experiments are used when it is necessary to test complex hypotheses about the relationships between variables. The general form of such a hypothesis is: "If A1, A2, ... Ax, then B." Such hypotheses are called complex, combined.

In a factorial experiment, as a rule, two types of hypotheses are tested:

1) hypotheses about the separate influence of each of the independent variables;

2) hypotheses about the interaction of variables, namely, how the presence of one of the independent variables affects the effect of the impact of another variable.

Factorial design of the experiment is to ensure that all levels of independent variables are combined with each other. The number of experimental groups is equal to the number of combinations of levels of all independent variables.

Factorial designs for independent variables and two levels of type 2x2. To draw up a plan, the principle of balancing is applied. The 2x2 design is used to identify the effect of two independent variables on one dependent variable. The experimenter manipulates possible combinations of variables and their levels.

Plan 3x2 or 3x3 is used in cases where it is necessary to establish the type of dependence of one dependent variable on one independent variable, and one of the independent variables is represented by a dichotomous parameter.

The first independent variable varies simply: there is a factor - there is no factor. The second independent variable is the levels, for example the difficulty factor. This is a 3x2 plan.

The 3x3 plan option is used when both independent variables have several levels, and it is possible to identify the types of relationship between the dependent variable and the independent ones.

Lecture 2. Planning a correlation study

Plan:

1. The concept of correlation research.

2. Types of plans for correlation research.

Similar information.

In order to find out its effect on the dependent variable.

Dependent variable- in a scientific experiment, a measured variable, changes in which are associated with changes in the independent variable.

The independent variable, for example, in a psychological experiment, can be considered the intensity of the stimulus, and the dependent variable is the ability of the subject to feel this stimulus.

Types of relationship between variables

The dependent variable is not sensitive to changes in the independent variable.
Monotonically increasing dependence: an increase in the values of the independent variable corresponds to a change in the dependent variable.
Monotonically decreasing dependence: an increase in the values of the independent variable corresponds to a decrease in the level of the independent variable.
Non-linear dependence of the U-shaped type - found in most experiments in which features of the mental regulation of behavior are highlighted
Inverted U-shaped dependence - obtained in numerous experiments and correlation studies.
Complex quasi-periodic dependence of the level of the dependent variable on the level of the independent.

Wikimedia Foundation. 2010 .

See what "Dependent variable" is in other dictionaries:

DEPENDENT VARIABLE- (eng. dependent variable) variable, which is influenced by another factor in the experiment (independent variable). See Lab Experiment... Great Psychological Encyclopedia

See DEPENDENT VARIABLE. Antinazi. Encyclopedia of Sociology, 2009 ... Encyclopedia of Sociology

DEPENDENT VARIABLE, see VARIABLE ... Scientific and technical encyclopedic dictionary

- (dependent variable) A variable on the left side of the regression equation whose change is correlated with changes in the causal variables, that is, the variables on the right side of the equation. For example, in a linear regression equation yi = α+βxi+γzi+εi where i =… … Economic dictionary

Dependent variable- - see Function ... Economic and Mathematical Dictionary

dependent variable- — [Ya.N. Luginsky, M.S. Fezi Zhilinskaya, Yu.S. Kabirov. English Russian Dictionary of Electrical Engineering and Power Engineering, Moscow, 1999] Electrical engineering topics, basic concepts EN dependent variable ... Technical Translator's Handbook

dependent variable- priklausomasis kintamasis statusas T sritis fizika atitikmenys: engl. dependent variable vok. abhängige Veränderliche, f rus. dependent variable, fpranc. variable dependante, f … Fizikos terminų žodynas

DEPENDENT VARIABLE- - a variable that changes under the influence of an independent variable and takes on different values. For example, if the nature of formal relationships in a dyad of employees of an organization acts as an independent variable ... ... Encyclopedic Dictionary of Psychology and Pedagogy

dependent variable- A variable whose variability we seek to explain by the influence of one or more independent variables. The distinction between dependent and independent variables usually rests on substantive considerations. Synonyms: criterion variable, ... ... Dictionary of Sociological Statistics

Dependent variable- - a variable that changes under the influence of another (independent) variable ... Social Work Dictionary