Mutually exclusive stats homework

In summary, when given P(A) = 0.8 and P(A or B) = 0.9, the value of P(B) can be determined using the formula P(A and B) = P(A) x P(B) if A and B are independent. However, if A and B are mutually exclusive, the formula P(A or B) = P(A) + P(B) can be used to find P(B). The value of P(A and B) can also be calculated using the formula P(A and B) = P(A) x P(B).
  • #1
daewoo
25
0

Homework Statement


Suppose that P(A) = 0.8 and P(A or B) = 0.9 , determine P(B) If
a) A and B are independent
b) A and B are mutually exclusive


Homework Equations


for Independence P(A and B) = P(A) x P(B)
for Mutually Exclusive P(A or B) = P(A) + P(B)


The Attempt at a Solution


for A) just by the formula i can say that P(A and B) = P(A) x P(B)
but i don't see still how i can find P(B), the P(A or B) part is really confusing to me.
 
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  • #2
For not mutually exclusive, part (A), p(A or B)= P(A)+ P(B)- P(A and B). Put the values into both that AND P(A and B)= P(A)xP(B).
 
  • #3
hm thanks, but how do you find out what P(B) alone is because i can't use that formula anyways.
 
  • #4
You can't use WHAT formula? And why not?
 

What does it mean for two statistical events to be mutually exclusive?

Mutually exclusive events are events that cannot occur at the same time. This means that if one event happens, the other event cannot happen. In statistical terms, this means that the probability of both events occurring is equal to zero.

Can two mutually exclusive events both have a probability greater than zero?

No, two mutually exclusive events cannot both have a probability greater than zero. As mentioned before, the probability of both events occurring is equal to zero. Therefore, if one event has a probability greater than zero, the other event must have a probability of zero.

How do you calculate the probability of two mutually exclusive events?

The probability of two mutually exclusive events can be calculated by adding the individual probabilities of each event. This is because, since the events are mutually exclusive, the probability of both events occurring at the same time is equal to zero.

What is the difference between mutually exclusive events and independent events?

Mutually exclusive events are events that cannot occur at the same time, while independent events are events that have no effect on each other. In other words, the outcome of one event does not affect the outcome of the other event. Mutually exclusive events have a probability of zero, while independent events have a non-zero probability.

How can you tell if two events are mutually exclusive?

To determine if two events are mutually exclusive, you can use a Venn diagram. If the two events have no intersection (i.e. they do not share any outcomes), then they are mutually exclusive. Another way is to see if the probability of both events occurring at the same time is equal to zero.

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