Calculate distinct count of active users monthly and average for multiple months

[Surya9]

I have a table having users activity (userid, points, monthid, yearid)
I have to create a measure that calculate distinct users count monthly, if multiple months is selected then calculate distict users monthly and then find the average among the months

[Surya9 · Accepted solution]

I got the solution 
Measure =

var _b = SUMMARIZE(table,table[monthid],"Users",DISTINCTCOUNT(table[userid]))

return AVERAGEX(_b,[Users])