Definition of correlation
1. Concept of correlationIn probability and statistics, the correlation indicates the strength and direction of a linear relationship and proportionality between the two statistical variables. When one of these values vary systematically from homonyms values of the other two quantitative variables are correlated: If we have two variables (A and B) correlation to increase to values of B and vice versa do so also. The correlation between two variables does not imply, in itself, no causal relationship (see cum hoc ergo propter hoc).
Strength, meaning and form of the correlation
The relationship between two quantitative variables is represented by the line of best fit, drawn from the point cloud. The basic elements of a snap line and, therefore, a correlation, are strength, direction and shape:
• Extreme force as the case may be, measures the degree in which the line represents the point cloud: If the cloud is narrow and elongated, is represented by a straight line, which indicates that the relationship is strong; If the cloud of points has a tendency to elliptic or circular, the relationship is weak.
• The direction measures the variation of the values of B to A: If growing up the values of A in B do not, the relationship is positive; If growing up the values of A decrease of B, the relationship is negative.
• The form sets the type of line that defines the best fit: straight line, monotonic curve or the non-monotonic curve
2. Meaning of correlationThe term correlation is used with statistical functions, to refer to the movement of two or more variables on a consequence provided by function in study. The correlation basically occurs when two elements have harmony in variation, this harmony is dependent, i.e., stabilization of one depends on the position of the other. The operation of a correlation is very easy to appreciate in a graphic way, since lines that comprise indicate movement of the statistical study, if he defends or decreases steadily there is a correlation between the variables, but if this at some point breaks, you lose the sense.
An example of course, an investor makes a statistical analysis and graphic assets, takes as its main variables the value of the investment, the amount that has earned him as gain and time that used to make this succeed. If sales of the product are favorable, in the stipulated time, earnings repuntarán over, but with the same sense of the projection that was initially made to perform the calculation. There is correlation with statistics, the investor is happy, because the action is favorable, this correlated.
The correlation in daily life is ordered from mouth, so when you run an action in which it is known that there will be another sympathy exists in the system. A production line has correlation between their functions, to run it and make the products properly, a pre-established sequence must be followed, otherwise series production would not serve for nothing.
When it says that correlation differs from the coincidence, we make use of a likely appeal, i.e., know that the correlation is premeditated, planned their impulses and worked to keep it stable. It will always search the harmony of these in a mathematical function while they are fly, this so you throw consistent results with the matter that is being studied. In fields like the of physics, variables such as the electric current and the space in which it occurs, must maintain a constant harmonic correlation.
3. What is the correlationThe term correlation is usually used to indicate the correspondence or the reciprocal relationship between two or more things, ideas and people, among others.
Meanwhile, in probability and statistics, correlation is that which indicates the strength and the linear direction between two random variables.
It is considered that two quantitative variables present correlation one with respect to the other when the values of a vary systematically with respect to homonyms values of the other.
For example, if we have two variables that are called A and B, there the mentioned phenomenon of correlation if increasing values to make it also values corresponding to B and vice versa.
Anyway, vale clarify that correlation that may occur between two variables does not imply by itself in any kind of causation. The main components of a correlation of this type are: strength, direction and shape.