Question

The probabilities of the orphaned pets in 6 cities animal shelter being differt types of animals are given in the table. If a randonmly selected orphaned pet in St Louis animal shelter is a dog what is the probability that it is a mastiff?
I've tried adding them up and then dividing the other dogs into it but I'm not coming up with the answer.
Help Please!

Answer 1

@amistre64 can you help again? please

Answer 2

how well was my answer for the last one?

Answer 3

I didn't get the same question but one very similar and you were correct. Thank you!

Answer 4

yay!

Answer 5

The answer to this one is 21.04 but I can't figuire out how they got that

Answer 6

we got a solution for thisone to play with thats good

the total of stlouis is 55.49, which of course aint 100% is something im thinking of

Answer 7

the total row is a bit confusing unless

Answer 8

id have to play with this in excel to keep track of some ideas to iron out

Answer 9

ok thanks I'm still pluging numbers haha going insane

Answer 10

what ideas have you been working with, might give me some insight that im forgetting

Answer 11

Well Ive been trying to think now if maybe a percentage of the six cities is a factor. My first thought was that it didn't

Answer 12

I asked my friend but he said he just guessed so that doesn't help. :/

Answer 13

satellites and zarkon are the genuises on these types of questions ..... well, on all types really but yeah

Answer 14

nothing i do can get the solution :/ good luck to

Answer 15

Thanks for trying I do appreciate it!

Answer 16

What you need to do is look at the St-Louis category only. Now, since they are picking from the dogs only, then you only consider the dogs.

For all the dogs: you have 2.65+2.46+3.67+2.91 = 11.69
Now, the probability of getting a Mastif is 2.46/11.69 = 0.2014 = 21.04%

Why can we do this? Because these percentages are just proportions. We don't have the raw numbers of dogs given, but that's ok. If this troubles you, you can think of multiplying all these numbers by 100, so you have 246 Mastifs and 1169 dogs. Thus, the probability of getting a mastif is 246/1169 = 0.2104

Answer 17

Well let me phrase that a bit differently. They are not necessarily picking from just the dogs, but the problem says that the pet they selected is a dog, so given that information, what probability is it that it's a Mastiff?

Answer 18

This is really just a form of a conditional probability:
\[P(\text{Mastiff}\mid\text{a dog})=\frac{P(\text{Mastiff} \cap \text{a dog})}{P(\text{a dog})}\]