Average of a distinct count based on criteria

[XLearn]

Hi,
I'm new to power pivots and dax formulas.

Does anyone know how I can work out the average value of distinct count based on a criteria?
Let's assume I have the tables below

Customer Table
Customer - Region
a - AA
b - AA
c - BB
d - CC


Product Table
Product - Type
1 - X
2 - X
3 - Y
4 - Z

Sales Table

Time - Product - Customer
Day 1 - 1 - a
Day 1 - 2 - a
Day 1 - 3 - a
Day 1 - 1 - b
Day 1 - 2 - c

On any given day (which I can use a power pivot filter for) how do I create a DAX formula that tells me region AA saw 3 unique product types purchased?

Hoping this is easy enough for the experts.
Thanks

 

[Matt Allington]

You need this measure. =distinctcount(sales[product])

you cna then filter on day and region, and the above will give you the result. If you want to know region a specifically, then you need this.

Calculate(distinctcount(sales[product]),customer[region]="AA")

 

[XLearn]

Thanks Matt,

This works perfectly when I need to see results for just one region. But how do I tweak this so it shows me the average number of product types purchased by all regions.

So using my above example region AA saw 2 product types purchased (X & Y) whereas regions BB and CC saw 1 product type purchased.
So using my formula if I applied no filter to my power pivot I would like it to display the result 1.33 which is the average of 2,1 & 1 : (2+1+1)/3

Hopefully this makes sense.
XLearn