Line Plots · Hard problem

A line plot shows how much snow fell on each of $8$ days, in inches. Above $\dfrac{1}{8}$ there are $3$ X's, above $\dfrac{3}{8}$ there are $2$ X's, above $\dfrac{1}{2}$ there are $2$ X's, and above $\dfrac{7}{8}$ there is $1$ X. How much more snow fell in all on the days with more than $\dfrac{1}{4}$ inch than on the days with less than $\dfrac{1}{4}$ inch?