Calculation of Correlation Coefficient (Leaving Cert Mathematics): Flashcards

$r$

Strength and direction of linear relationship

$-1$ to $+1$

Perfect positive correlation

Perfect negative correlation

No linear correlation

Number of data points

Organise data: table with $x$, $y$, $x^2$, $y^2$, $xy$

Calculate $sum x$, $sum y$, $sum x^2$, $sum y^2$, $sum xy$

Substitute values into formula

Direct correlation

Inverse correlation

Weak or no correlation

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