How can the average rate of change be found using a discrete graph?

In general, the average rate of change of f (x) on the interval a, b is given by f(b) – f(a) / b – a. The average rate of alteration of a function, f (x) on an interval is well-defined to be the variance of the function values at the endpoints of the interim divided by the difference in the x values at the endpoints of the interval. this is also known as the difference quotient that tells how on average, the y values of a function are changing in connection to variations in the x values. A positive or negative rate of change is applicable which match up to an increase or decrease in the y value among the two data points. It is called zero rate of change when a quantity does not change over time.

Ineed show the photo because i need more information

Its d so thats how it would would back from 1.0 form three four two