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External analysis

5.2 Correlation

Correlation can provide a measure of how strong the relationship is between two sets
of data:

Correlation 0 1

Not Perfectly
Correlated Correlated

5.3 The coefficient of determination

This squares the correlation in order to express the strength of the relationship
between the variables as a percentage.

The coefficient of determination represents the proportion of the total variation in the
y variable that is explained by the regression equation.

Illustrations and further practice

Now review the illustration on the use of linear regression.

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