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Topic: Correlation


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In the News (Sun 19 Nov 17)

  
  CORRELATION
Direct relationships (positive correlations) exist when high scores on one variable are associated with high scores on another variable, as when intelligence is positively correlated with grade point average.
Inverse relationships (negative correlations) exist when high scores on one variable are associated with low scores on a second variable, as when the amount of sleep one gets is negatively correlated with levels of irritability and anxiety.
Demonstrating that a correlation exists does not prove that changes in one variable are the cause of changes in the other, partly because other factors which are undetected may be influencing both known variables.
www.mcckc.edu /longview/ctac/psych3.htm   (381 words)

  
  Correlation
Correlation is a statistical technique which can show whether and how strongly pairs of variables are related.
Although this correlation is fairly obvious your data may contain unsuspected correlations.
Correlation works for data in which numbers are meaningful, usually quantities of some sort.
www.surveysystem.com /correlation.htm   (819 words)

  
  Tetrachoric and Polychoric Correlation
The tetrachoric correlation assumes that the latent trait T is normally distributed.
The tetrachoric correlation r* is readily interpretable as a measure of the association between the ratings of Rater 1 and Rater 2.
This is a generalization of the polychoric correlation, though perhaps we should reserve that term for the latent bivariate normal case.
ourworld.compuserve.com /homepages/jsuebersax/tetra.htm   (4021 words)

  
  Primer on Correlation Coefficients
The P value falls with stronger correlations: P = 0.005 for an r of 0.6 and P < 0.0001 for an r of 0.9.
Although correlation coefficients are an efficient way to communicate the relationship between two variables, they are not sufficient to interpret a relationship.
For example, a strong positive correlation between influenza and pneumococcal vaccination rates measured among physicians should be interpreted differently than the same coefficients measured among clinics.
www.acponline.org /journals/ecp/mayjun01/primer_correlcoeff.htm   (750 words)

  
  PA 765: Correlation
Beside Pearsonian correlation (r), the most common type, there are other special types of correlation to handle the special characteristics of such types of variables as dichotomies, and there are other measures of association for nominal and ordinal variables.
Also, there is partial correlation, which is the correlation of one variable with another, controlling both the given variable and the dependent for a third or additional variables.
Eta, the coefficient of nonlinear correlation, known as the correlation ratio, is discussed in the section on analysis of variance.
www2.chass.ncsu.edu /garson/pa765/correl.htm   (3727 words)

  
 THE CORRELATION COEFFICIENT
This correlation squared is.45, which means that across the fourteen nations constituting the sample 45 percent of their variance on the two variables is in common (or 55 percent is not in common).
Concerning positive correlation, this desire is clearly reflected in Figure 6.2c, for as the magnitude of a case on one variable is high, it is high on the other; as it is low on one, it is low on the other.
The partial correlation of.13 is quite a drop from the original correlation of.61 between illiteracy and infant mortality, a sharp decrease from 37 percent to 2 percent covariation.
www.mega.nu:8080 /ampp/rummel/uc.htm   (11715 words)

  
 Correlation at Trade10.com- The science of trading market momentum for stocks, options, futures and bonds.
Correlation analysis is a measure of the degree to which a change in the independent variable will result in a change in the dependent variable.
Correlation can also be used for a study between an indicator and a stock or index to help determine the predictive abilities of changes in the indicator.
In other words, the correlation between two things in the markets does change over time and so a careful understanding that what has happened in the past may not predict what will happen in the future should be part of any basis in trading financial instruments in the market.
trade10.com /Correlation.html   (1032 words)

  
 Correlation
Correlation is the statistical concept which describes the amount and type of relationship between two variables.
Using correlations we can talk about whether two variables are related to each and how that relationship functions--whether it is a positive or direct relationship or a negative or inverse relationship.
The correlation coefficient for the dots in the restricted range (above the green line) is spuriously low compared the r computed on the whole scatterplot.
www.utah.edu /stat/introstats/web-text/Correlation   (7051 words)

  
 [No title]   (Site not responding. Last check: )
The correlation coefficient r is a quantitative measure of association: it tells us whether the scatterplot tilts up or down, and how tightly the data cluster around a straight line.
The correlation coefficient is appropriate only for quantitative variables, not ordinal or categorical variables, even if their values are numerical.
Correlation is a measure of association, not causation.
www.stat.berkeley.edu /users/stark/SticiGui/Text/ch4.1.htm   (632 words)

  
 Correlation Analysis :: Linear Regression Analysis (Data Analysis)
Correlation is a method for establishing the degree of probability that a linear relationship exists between two measured quantities.
When there is no correlation between the two quantities, then there is no tendency for the values of one quantity to increase or decrease with the values of the second quantity.
The arrangement of the elements in the correlation coefficient matrix corresponds to the location of the elements in the covariance matrix, as described in Covariance.
www.mathworks.com /access/helpdesk/help/techdoc/data_analysis/bqmzngs-1.html   (535 words)

  
 Correlation - European Network
Researchers, policy makers, representatives from sex work, drug use, Roma and migrant communities had the opportunity to follow more than 60 workshops and presentations, interactive discussions, a film programme and satellite meetings of the SWAN and the INPUD networks.
Correlation network will publish all presentations and outcomes of the conference on hard copy and on this website as soon as possible.
We thank again all participants, speakers, co-funders and the Bulgarian hosts which all helped to make this event possible.
www.correlation-net.org   (568 words)

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