Answer
.02
Work Step by Step
We are given two points: (1,.02) and (3, .06). Note, time is the independent variable as how much snow there is does not change what time it is. Meanwhile, the time of day changes how much snow there is, making inches of snow the dependent variable. In order to find the slope, we use the following equation: $ \frac{y_{2}-y_{1}}{x_{2}-x_{1}}$. Thus, we obtain:
$\frac{.06-.02}{3-1}=\frac{.04}{2}=.02$