The following grafic show us the ages of the surfaces of the Moon that we study:
How do we read this grafic?
In the axis X we put the diameter of the craters, in the axis Y we put the number of the craters in one acoording the their diameter. With these dates, in the grafic we obtein a interval inside of a zone, and this zone is the age that we went.
How do we interpret this grafic?
This grafic show that we studied: a surface of the Moon with many craters and diameters of the craters big is older (always we compare with a other surface).
If we have craters in one with a diameter between 4 and 8 Km, this surface will be old, but will be younger that a surface with craters in one with a diameters between 4 and 8 Km.