Statistics
Probabilty Help - The OR or UNION symbol ∪
The OR or UNION symbol U usually means we are going to extend the values we are allowing:
E.g. 1:
A
We shade in A.
A ∪ B
The shaded area has been EXTENDED to include B.
E.g. 2:
A' (NOT A)
Everything outside A has been shaded.
A' ∪ B
The shaded area has been EXTENDED to include all of B.