S1.4 - Correlation and regression

Scatter diagrams.; Linear regression.; Calculation of the equation of a linear regression line using the method of least squares.; Students may be required to draw this regression line on a scatter diagram.

Use scatter diagrams to connect the rule to the data and decision in the question.

This matters because scatter diagrams determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply scatter diagrams to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: Scatter diagrams is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Explanatory (independent) and Use to make predictions within the range of values of the response (dependent) variables. explanatory variable and the dangers of extrapolation.; Applications and interpretations.; Derivations will not be required.; Variables other than x and y may be used.; Linear change of variable may be required.

Use explanatory (independent) to connect the rule to the data and decision in the question.

This matters because explanatory (independent) determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply explanatory (independent) to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: Explanatory (independent) is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

The product moment correlation Derivations and tests of significance will not be required. coefficient, its use, interpretation and limitations.

Use product moment correlation to connect the rule to the data and decision in the question.

This matters because product moment correlation determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply product moment correlation to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: Product moment correlation is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.