Bivariate data has two variables, where each data point for one variable has a corresponding data point for the other variable.

A scatter graph is a visual representation for bivariate data. It can be useful when determining the nature of the relationship between the variables.

An independent (explanatory) variable is a measure that is predicted to have an effect on another variable.

A dependent (response) variable is a measure whose value is predicted to be affected by an explanatory variable.

Checking understanding of scatter graphs

Maths

Checking understanding of correlation

Estimating from scatter graphs

Interpolation versus extrapolation

Outliers in scatter graphs

Constructing time series graphs

Interpreting time series graphs

Problem solving with scatter graphs and time series

In the prior unit, pupils explored different graphs and charts as a way of presenting data visually. Pupils were introduced to scatter graphs and learnt how to construct them. In this unit, this understanding is extended to using a line of best fit to allow interpolation.

In this unit pupils will learn how to interpret and extract data from scatter graphs and time series graphs.

Graphical representations of data: scatter graphs and time series

Correlation describes the extent to which the relationship is close to a linear relationship.

A line of best fit is a line where the distance between each data point and the line is minimised.

Interpolation is the process of estimating unknown values that are inside the range of existing data.

Extrapolation is the process of estimating unknown values that are outside the range of existing data.

An outlier is a data point that is extremely large or small compared to the rest of the dataset. Visually, outliers lie far away from where the majority of the results are clustered.

Time series graphs show data over a time period. The time period is always shown on the x-axis. Data points are joined chronologically by line segments.

Graphical representations of data: scatter graphs and time series

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