Explanation:
x represents the hours of rain (0 to 6).
y (= f(x)) represents the inches of rain fallen during the given hours.
the domain is the interval or set of the valid x-values. in our case [0 .. 6].
the range is the interval or set of the valid y-values. in our case that is [0×0.2 .. 6×0.2] = [0 .. 1.2]