Question 1123012:  53% of the residents in a town own a dog. 64% own a cat. 49% of the dog owners also own a cat. If a resident is chosen at random. What are the probabilities for the following?  
-Probability(own a dog) 
-P(own a cat) 
-P(own a cat and a dog) 
-P(own a dog given they own a cat) 
 Answer by Theo(13342)      (Show Source): 
You can  put this solution on YOUR website! probabilities and are related in that, if something has happened 54% of the time in the past, then, unless something changes, it is reasonable to expect that it will happen approximately 54% of the time in the future as well.
 
 
that's why, it 54% of the people own dogs, then, it is reasonable to expect that, if you pick a person randomly out of the same population, the probability that the person will own a dog is 54%.
 
 
therefore:
 
 
given that 54% own dogs and 64% own cats and 49% own both, ........
 
 
p(own a dog) = .54 
p(own a cat) = .64 
p(own a cat and a dog) = .49
 
 
p(own a cat given that they own a dog) requires some logic and a formula that was developed to handle this situation.
 
 
you have 54% own a dog. 
you have 49% own a cat and a dog.
 
 
given that a person owns a dog, the probability that the same person also owns a cat is .49 / .54 = .907407407.
 
 
the formula developed to handle this situation is:
 
 
p(owns a cat given owns a dog) = p(owns a cat and a dog) divided by p(owns a dog).
 
 
the generalizerd formula is:
 
 
p(A given B) = p(A and B) / p(B)
 
 
 
 
 
 
 
 
 
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