Scatter Graphs and Triangular Graphs

Think about the possible links that scatter and triangular graphs have with other geographical techniques in your study guide.

Scatter graphs:

• use linear regression analysis to calculate the regression line to achieve a greater level of accuracy
• assuming there are sufficient data, you could use the Spearman rank correlation coefficient or the Pearson product moment correlation coefficient to test whether there is a significant statistical relationship

Additional content on Scattergraphs
The following practice questions have been sourced from classroom resources and from TeachItGeography. You can also find additional material on the SQA website under Geography – Advanced Higher – Past Papers and Marking Instructions.

Question 1
These have the potential to allow you to investigate the relationship between two sets of data. The graph below was produced by Excel giving a ‘line of best fit’, which it has done with a black line. However, notice the ‘outlier’ or ‘residual’ i.e. points that lie some distance away from the line. These can be useful as they can give you an idea of a further area for investigation (i.e. go back and sample again).

(a). Which point is a residual (circle it) and why do you think it might be there?

(b). Pretend the point was not there – draw another line of best fit.

Additional content on Triangular Graphs
The following practice questions have been sourced from classroom resources You can also find additional material on the SQA website under Geography – Advanced Higher – Past Papers and Marking Instructions.

Question 1
These are plotted on special graph paper in the form of an equilateral triangle. It can only be used for a whole figure that can be broken into 3 components. Once plotted clusters can emerge and classifications can also take place.

What are the primary, secondary and tertiary percentages for the following:

Question 2
A triangular graph is used to show geographical phenomena composed of three different parts. The graph can best be understood by identifying the components at the apexes of an equilateral triangle. The graph below identifies a schema for simple soil colour identification. When soils are freely drained soil colour can be traced back to three main colours that produce:

• black (in humus-rich soils)
• red (in iron-rich soils)
• white (in soils rich in silicates and salts).

If perpendicular lines are dropped from each apex to the opposite side of the triangle then movements along a colour gradient can be read. Thus a chestnut coloured soil would contain no white and equal amounts of black and red pigments. Explain the colour of the following soils:

• Orange
• Dark grey
• Chocolate

Question 3
The graph below shows the percentage of working population employed in agriculture, industry and services, has numbers arranged in a counter-clockwise direction. Note how the internal lines extended beyond the edges of the triangle make interpreting this graph simpler. The letters on the graph refer to the mix of the three variables.

Task:
(a) Plot the data on to a triangular graph and insert an appropriate letter for each country. (Download a Triangular Graph template by clicking here)
(b)Explain which countries

have the highest standard of living?

have the lowest standard of living?

you think are developing countries?