Average sales before price change & after price change

HI excel users
I am working with some data to calculate price elasticity. I am looking for the average sales units for the 3 weeks prior to pricing change, as well as 3 weeks after price change to calculate the impact.
I am sure there is a simple method using Averageifs, however I am struggling.
My data is attached
I have approximately 10,000 lines so need to do this automatically
Can anyone help please?
thanks

hi, welcome to the board.

the request seems reasonable enough, but are you able to provide a slightly larger dataset as, presumably, in real-life you must have multiple products, the price changes for which will surely occur in different weeks ?

further, will you only have one price change for a given product within the dataset ?
i.e. could Product A conceivably have 2 price changes between weeks 16 & 23, and if so, what do you wish to do in your calculation ?