Question

Marginal Probabilities

So we have a joint probability P(A and B)

Lets say I want to find P(A).

Which of the following is true?

1) P(A) = P(A and B) + P(A and B')

or

2) P(A) = P(A and B) + P(A' and B)


Thank you

Answer 1

@robtobey @e.mccormick @robtobey

Answer 2

you can use a venn diagram to show this

Answer 3

well the question is handwritten by me so you cant just say me the answer

Answer 4

hm

Answer 5

int. = intersect

Answer 6

so I guess its the first expression 1) P(A) = P(A and B) + P(A and B')

Answer 7

P(A) = P(A and B) + P(A and B') its that right ?

Answer 8

yes

Answer 9

Thank you

Answer 10

do you see how they stand for regions