What two numbers go there (Part 2)

—the graph shows how fast a strand of human hair grows. how many inches would the hair have grown in 5 months

Which term best describes the association between variables a and b? no association a negative linear association a positive linear association a nonlinear association a scatterplot with an x axis labeled, variable a from zero to ten in increments of two and the y axis labeled, variable b from zero to one hundred forty in increments of twenty with fifteen points in a positive trend.

Just tell me how to set up the equation.