Scatter Plot Graphs
A scatter diagram visually displays the relationship between the two chosen soil quality indicators.
A positive upward relationship occurs when data points with higher values on the horizontal (x-axis) correspond to higher values on the vertical (y-axis).
A negative downward relationship occurs when data points with higher values on the horizontal (x-axis) correspond to lower values on the vertical (y-axis).
If the data points are scattered with no obvious trend then there is no simple relationship between the two soil quality indicators.