confidence int. length known for prop.: how to find margin?

S

statshelp

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• Apr 9, 2008

• #1

If you know the length of a confidence interval for a proportion, How would you find the margin of error?

Please Help!

 

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royhaas

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• Apr 9, 2008

• #2

Re: confidence interval question

How do you calculate the length of a confidence interval?

 

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statshelp

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• Apr 9, 2008

• #3

Re: confidence interval question

Max confidence interval - Min confidence interval / 2

 

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royhaas

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• Apr 9, 2008

• #4

Re: confidence interval question

No, the length is just the difference between the two endpoints of the interval. Now use the formulas for those endpoints and subtract them.

 

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statshelp

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• Apr 9, 2008

• #5

Re: confidence interval question

Ok so once I find the length, I then divide by 2, to find the margin of error?

 

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royhaas

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• Apr 9, 2008

• #6

Re: confidence interval question

Just like the calculation implies.

 

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statshelp

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• Apr 9, 2008

• #7

Thanks, it just seemed to easy.