I am trying to recreate this attached chart with my own data, and I am so stuck – specifically on two things. First, I want to group the lower numbers together (<30) and upper numbers together (>80). To do that, Tableau seems to make me turn the x-axis thing (HERS rating) into a Dimension and then do Groups of those lower and upper numbers. (Is there another way? Is there a way to group Measures? I couldn’t’ find it.)

Second, on the same chart, I also want to show some vertical reference lines including average HERS Score. But to do that I guess it would have to be a Measure and not a Dimension (right?) It won’t let me find the average of a Dimension. It won't let me insert vertical reference lines at all, just horizontal ones.

How can I do all of those things elegantly in one chart? Are HERS Ratings (or HERS Scores) a Dimension or a Measure? (A HERS Score rates the energy performance of houses on a 1-100 scale.)

Thank you for any advice.