I am trying to create a bar graph with weeks on the x-axis and volumes on the Y-Axis. After a certain date (i.e. 30 Oct) there is a massive jump in volume due to some initiative that we are undertaking. I am trying to add additional expressions (i.e. Lines) to the chart that show the massive jump in weekly averages for Pre-30 Oct and another for Post- 30 Oct.
Didn't know you could do that, so thanks very much for your response.
However, it's not quite what I am looking for. I am building a dashboard that calls out the jump in the average number of weekly sign ups to a website (the time periods are not the same, therefore averages are used to even it out).
I have built an expression that computes the average of the 6 months prior to the reference date, 30 Oct. and the results post 30 Oct. I want these to be horizontal lines on the time series chart so that I can easily show what the stat means.
In fact, I found that adding a Total Column Worked!