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AS Statistics Revision
Statistics 1 Chapter 6
Key points to remember
Correlation = a measure of the degree of linear association
between two variables.
Positive correlation = both variables increase together
Negative correlation = one variable increases while the other
Scatter diagram = a graphical representation of pairs of
observations plotted on a graph.
r = 1 1<r<0 r=0 0<r<1 r = 1
Sxx = x² ((x)² ÷ n)
Syy = y² ((y)² ÷ n)
Sxy = xy ((xy) ÷ n)
Product moment correlation coefficient
linear association r = Sxy ÷ (Sxx Syy)