Rolling averages in widgets

Hi all, 

I need help with a couple of widgets, that to be honest, I'm not even sure where to start - I'm struggling with which dates to use where, but everything should be based around performance date as opposed to order or attended dates.....I'm trying to recreate some graphs that have been created by our research team in excel & I'd like to take the manual work from them if possible by adding it to our exhibitions dashboard. The graphs currently look like the 2 below - but I'm open to anything that will give them the same data. 

1. Average daily ticket sales per week - as the image shows, the daily average number of tickets for each day of the week during a specific time period of 4 weeks (or 28 days).

        2. Rolling four week average ticket sales by day of the week 

thanks for any advice!

jo