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#26 2013-06-21 08:45:58

Al-Allo
Member
Registered: 2012-08-23
Posts: 294

Re: Little question (Probability)

could you show me in details my error pls ?

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#27 2013-06-21 08:49:55

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

You are correct here, all three hitting:

0.4*0.3*0.8 because you computed three arrows being fired.

Here you are incorrect
0,4 * 0,3= 0,12 or 0,4*0,8= 0,32 or 0,3*0,8=0,24 you only fired 2 arrows what about the third? The one that missed?


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

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#28 2013-06-21 09:01:54

Al-Allo
Member
Registered: 2012-08-23
Posts: 294

Re: Little question (Probability)

Ok, must I see it that that way

1-No one gets-2 persons don't get it-1 person don't get it- every one gets it- 2 persons gets it- 1 person gets it = 0

???

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#29 2013-06-21 09:05:24

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Here is how to see it. If you tree these that is when you see the errors quickly. I will give you another approach

h means hit and m means miss. There are 3 2 hits and 1 miss. Do you see them?

For instance Tom hits, Alice hits and Julie misses. To get the probability for that just fill in

Tom = h = .4
Alice = h = .3
Julie = m = .2

.4*.3*.2 = .024

You do the other 2 and add them up


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

#30 2013-06-21 09:15:31

Al-Allo
Member
Registered: 2012-08-23
Posts: 294

Re: Little question (Probability)

AH......... ok, Sh... I should have done a drawing to help me see it. Ok, now, I know how to finish do it.

Here's, in the ordrer of the diagramm, the probabilities :

0.096+0.024+0.224+0.056+0,144+0,036+0,336+0,084=1

GOOD!
Thank you bobbym, I've learned from it !

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#31 2013-06-21 09:19:01

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Hi;
Did you calculate using the m's too?


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

#32 2013-06-21 09:20:39

Al-Allo
Member
Registered: 2012-08-23
Posts: 294

Re: Little question (Probability)

YEs, I've included the m's in the equation above. ALso, I got 0,392 for two persons hitting !

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#33 2013-06-21 09:22:41

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Very good! These problems can be tricky. I got the wrong answer too. You have to be careful. Now you can figure out 0,1,2,3 easily.]

See you later, I have to go.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

#34 2013-06-21 09:23:48

Al-Allo
Member
Registered: 2012-08-23
Posts: 294

Re: Little question (Probability)

Ok, bye and thank you again. If it happens again, I'll remember to do a drawing like yours !

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#35 2013-06-21 18:33:33

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Hi;

You are a fast learner.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

#36 2013-07-14 21:31:21

Angie Pop
Member
Registered: 2013-07-14
Posts: 3

Re: Little question (Probability)

I have just had a bit of look at these particular posts regarding "A little question on Probability".  I was on the understanding that this forum was for Maths is Fun for Kids from Kindergarten to Year 12, just looking at these particular posts I don't se how this forum would assist me if I was to ask about "Probability - Chance and Data"  - for Kids

Thank you

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#37 2013-07-14 22:46:29

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Hi Angie Pop;

Welcome to the forum.

I don't se how this forum would assist me if I was to ask about "Probability - Chance and Data"  - for Kids

Hmmm, might be worth a shot to post your question and see what the tooth fairy brings.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

#38 2013-07-14 23:45:29

Angie Pop
Member
Registered: 2013-07-14
Posts: 3

Re: Little question (Probability)

That is a fair response, quite amazed at what I looked at in previous posts, is all, the course that I am doing is for Kids in Early Primary to Mid School and Upper Primary, just looking at the Maths is Fun website, seems more simplistic

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#39 2013-07-15 00:01:26

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,571

Re: Little question (Probability)

Hi;

The MIF site has tons of stuff on probability.

http://www.mathsisfun.com/data/probability.html

http://www.mathsisfun.com/probability_line.html

When the kids have a question about any of it, that is when it is time to come in here.

Then they can learn from Yoda, the Jedi master who instructed me.

I never thought I would get a chance to use that quote from "The Empire Strikes Back!"


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

Online

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