Question 140829: How does correlation analysis differ from regression analysis?
What does a correlation coefficient reveal?
State the quick rule for a significant correlation and explain its limitations.
What sums are needed to calculate a correlation coefficient?
What are the two ways of testing a correlation for significance?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In probability theory and statistics, correlation, (often measured as a correlation coefficient) , indicates the strength and direction of a linear relationship between two random variables. In general statistical usage, correlation or co-relation refers to the departure of two variables from independence. In this broad sense there are several coefficients, measuring the degree of correlation, adapted to the nature of data.
A number of different coefficients are used for different situations. The best known is the Pearson product-moment correlation coefficient, which is obtained by dividing the covariance of the two variables by the product of their standard deviations. Despite its name, it was first introduced by Francis Galton.
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Regression analysis is a technique used for the modeling and analysis of numerical data consisting of values of a dependent variable (response variable) and of one or more independent variables (explanatory variables). The dependent variable in the regression equation is modeled as a function of the independent variables, corresponding parameters ("constants"), and an error term. The error term is treated as a random variable. It represents unexplained variation in the dependent variable. The parameters are estimated so as to give a "best fit" of the data. Most commonly the best fit is evaluated by using the least squares method, but other criteria have also been used.
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State the quick rule for a significant correlation and explain its limitations.
See the top of p.494 of your statistics textbook.
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What sums are needed to calculate a correlation coefficient?
See page 490 of your textbook
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What are the two ways of testing a correlation for significance?
See the discussion starting on the bottom of page 490.
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Cheers,
Stan H.
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