Content-specific conceptual understandings
Linear correlation of bivariate data.
Pearson’s product-moment correlation coefficient, r.
Technology should be used to calculate r. However, hand calculations of r may enhance understanding.
Critical values of r will be given where appropriate.
Students should be aware that Pearson’s product moment correlation coefficient (r) is only meaningful for linear relationships.
Scatter diagrams; lines of best fit, by eye, passing through the mean point.
Positive, zero, negative; strong, weak, no correlation.
Students should be able to make the distinction between correlation and causation and know that correlation does not imply causation.
Equation of the regression line of y on x.
Use of the equation of the regression line for prediction purposes.
Interpret the meaning of the parameters, a and b, in a linear regression y=ax+b.
Technology should be used to find the equation.
Students should be aware:
• of the dangers of extrapolation
• that they cannot always reliably make a prediction of x from a value of y, when using a yon x line.
The relationship between x and y can be modelled using the formula y = kxn, where k ≠ 0, n ≠ 0, n ≠ 1.