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April 02, 2026, 01:51:23 pm
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Author Topic: Solving for n in probability  (Read 2224 times)  Share 

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Asx4Life

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Solving for n in probability
« on: October 28, 2011, 05:32:35 pm »
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Can someone please explain how I can use the table method to find values of n.


ThanKs  :D
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Andiio

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Re: Solving for n in probability
« Reply #1 on: October 28, 2011, 06:54:50 pm »
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Quote from: Asx4Life on October 28, 2011, 05:32:35 pm
Can someone please explain how I can use the table method to find values of n.


ThanKs  :D

Table method?
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Asx4Life

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Re: Solving for n in probability
« Reply #2 on: October 29, 2011, 12:47:45 pm »
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Anyone know about this method? =(
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Panicmode

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Re: Solving for n in probability
« Reply #3 on: October 29, 2011, 01:51:12 pm »
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Yah, it involves generating a table in the graphs/tabs menu of the Cas calculator from the cumulative distribution and working down till you find the probability that you require.

For instance, if you were asked the question, how many times do I have to flip a coin in order that the probability of obtaining a head is greater than or equal to 90%?

That's a question where it would be used. The idea is to solve for the number of trials given the probability of an event occurring. The problem is, the calc is so fugggn slow that the best method is to generate a table with n=1, 2, 3 etc. and thee finding the value where the probability is greater than or equal to what is being looked for.
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Shiverz360noscopez

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Re: Solving for n in probability
« Reply #4 on: October 29, 2011, 04:55:39 pm »
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there was a question in the 2009 Tech that was like this and in the answers they stated that you must use 'guess and check' -_-
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Menang

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Re: Solving for n in probability
« Reply #5 on: October 29, 2011, 05:03:22 pm »
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Actually, I need help with these sort of problems too! Anyone want to post a step-by-step method for my mathematical-failure of a brain?
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abeybaby

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Re: Solving for n in probability
« Reply #6 on: October 29, 2011, 06:20:51 pm »
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Here's a shot of some notes ive written for lectures, which show how to do this. I've only included the relevant bits, and ive taken some screen shots of my calculator so you guys know what you need to do. Ive taken the problem from the line that I circled in red. If i were to do something like this on an exam, i would use the method in shot no. 3, but having said that, I probably wouldnt be using this method at all.

just so you know: binomcdf(n,p,lower x,upper x)
                             binompdf(n,p,x)

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Asx4Life

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Re: Solving for n in probability
« Reply #7 on: October 29, 2011, 07:23:29 pm »
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Quote from: abes22 on October 29, 2011, 06:20:51 pm
Here's a shot of some notes ive written for lectures, which show how to do this. I've only included the relevant bits, and ive taken some screen shots of my calculator so you guys know what you need to do. Ive taken the problem from the line that I circled in red. If i were to do something like this on an exam, i would use the method in shot no. 3, but having said that, I probably wouldnt be using this method at all.

just so you know: binomcdf(n,p,lower x,upper x)
                             binompdf(n,p,x)



WOOO, Thanks you LEGEND````
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