Statistics
Probabilty - The AND or INTERSECTION symbol ∩
The AND or INTERSECTION symbol usually means we are going to RESTRICT the values we are allowing:
E.G. 1:
A
All values in A are shaded.
A∩B
We have RESTRICTED the shading to those parts of A which are also in B.
E.G. 2:
A' (NOT A)
All values outside of A are shaded.
A' ∩ B
We have RESTRICTED the shading to those parts outside of A which are also in B.