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April 28, 2024, 06:37:16 pm
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Author Topic: Probability Question  (Read 772 times)  Share 

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nerd

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Probability Question
« on: October 26, 2008, 06:36:06 pm »
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I'm having a little trouble with a question from Insight 2008 Exam 2, Question 4e) and 4f). I'm not even sure what they are asking!! (All this stuff about missclasification is confusing me, I think!)

I cbf writing the question out, cause it has a few parts, but I'm hoping someone has uploaded it somewhere on VN!

Thanks in advance...
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2008
Hebrew - 33 (scaled 44)   |   Maths Methods - 45 (scaled 48)

2009
Specialist Maths   |   Chemistry   |   English   |   Biology   |   Further Maths

ReVeL

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Re: Probability Question
« Reply #1 on: October 26, 2008, 07:25:17 pm »
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Lol.

Just looked at it.

I got NO IDEA wth its even asking either.

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ausyid

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Re: Probability Question
« Reply #2 on: October 26, 2008, 10:33:12 pm »
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Is this the butterfly thing?

From memory, the final question is ridiculous. You have to graph one against the other and then do something (perhaps find the intersection).

The other questions are straightforward once you figure out what its asking.
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nerd

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Re: Probability Question
« Reply #3 on: October 26, 2008, 10:43:05 pm »
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Yeah - it's the butterfly question! The rest was easy, just the last two questions were so hard!
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2008
Hebrew - 33 (scaled 44)   |   Maths Methods - 45 (scaled 48)

2009
Specialist Maths   |   Chemistry   |   English   |   Biology   |   Further Maths

Chocoholic

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Re: Probability Question
« Reply #4 on: October 26, 2008, 11:18:08 pm »
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Ok, this is what I understood from part (e).........

The probability of misclassification is the probability of saying a butterfly from group A is a B butterfly. For a butterfly to be classified in this group it needs to be less than 20 cm. However, the problem we have is that some A butterflies are actually greater than 20cm, and so would be classified as B butterflies (since B butterflies are greater than 20 cm).

So to find the probability of an A butterfly being misclassified you find the probability that it is greater than 20(integrate from 20 to infinity).

As for B butterlies, the are greater than 20 cm, so just find the prob. that they are less than 20cm.

I'll post the explanation to part (f) in a sec........i just need to eat first, lol, I'm hungry! :P
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