If we want to make a graph then can the staring points for x-axis and y-axis be different? For example; if the starting point of x-axis is 0 then can it be 10 for y-axis?
In the following graph, concentration and density are plotted. The starting point for x-axis is 0 while for y-axis it is 2. What does it mean? Does it mean that when concentration is 0, density is 0.95? It is impossible.
Best Answer
You can imagine the graph going over the whole real plane. The paper isn't large enough to show that, so we print the part of the graph that is of interest. In this case, we could extend the plot downward so we could show Density of zero. It looks like none of the curves would go through the new area, so (given the area of the printed page or window onscreen) no new information would be portrayed. Then we would have to shrink the part that is currently shown, so it would be harder to read values off the graph.
In this case, it doesn't make sense to extend the $x$ axis beyond $0\%$ to $100\%$, but the point is the same-display the region of interest. This tends to accentuate variation. In this case, it looks like the density increases a lot with concentration, but really it only increases in proportion to the concentration. That shows that the reader has to pay attention.