Question

If A and B are mutally exclusive events, P(A)=.26 and P(B)=.45 find:

(a) P(not A)
(b) P(AUB)
(c)P(A intersection not B)
(d)P(not A intersection not B)

Answer 1

(a) P(not A) = 1-P(A)

.45 = 1-.26

.45+.26 =.71

(b) P(AUB)

not sure about this one.


(c)P(A intersection not B)


not sure about this one either

(d)P(not A intersection not B)


P(not A intersection not B)=1-P(AUB)

1=1-.71

=.29

Answer 2

why do you have .45 = 1 - .26 for P(not A)?

Answer 3

for \(P(A\cup B)\) add the probabilities since they are disjoint

Answer 4

just so you know.... not A doesn't automatically mean B

Answer 5

Oh okay, so would it just be 1-.26=.74 since P(not A)=1-P(A)?

Answer 6

yes

Answer 7

So in that case would (c) be1-P(not(not A U not B))-P(not A intersection B)

= 1-.29+.45
=.26?

Answer 8

NO!

Answer 9

@JerJason,

Two events A and B are said to be mutually exclusive if\[P(A cupB)=P(A) + P(B)\]

Answer 10

That should be\[P(A \cup B)=P(A)+P(B)\]

Answer 11

If the events are mutually exclusive then\[P(A ∩ B)=0\]

Answer 12

Now use this information to answer your questions.