Yes, the graph provides a good visual representation of the relationship between the factors being investigated when there are only two variables being studied at a time.
Sometimes a third variable is represented on a negative y-axis which plays a minor role in any one of the factors that may be conveniently represented.
Since we can draw only 2-dimensional diagrams on a paper, therefore, graphs are restricted to a couple of variables.
The independent variable is usually represented on the x-axis and the dependent variable is represented on the y-axis.
Graphs tell us the pattern of variation of a quantity with respect to another.
I think the answer would be A. Density because many headlights could have the same density, but the rest of the analysis techniques would be specific to that crime.
