Need some help with stats, finding the sample size needed

pipe0076

New member
Joined
Jul 8, 2012
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2
Here is the problem:
According to an article the bottled water you are drinking may contain more bacteria and other potentially carcinogenic chemicals that are allowed by state and federal regulations. Of the more than 1500 bottle studied, nearly one-third exceeded government levels. Suppose that a department wants an updated estimate of the population proportion of bottled water that violated at least one government standard. Determine the sample size (number of bottle) needed to estimate this proportion to within +/-0.002 with 99% confidence.

I know which formula to use, but the value of p I should use is screwing me up. I know the Z score will be 2.575 and the SE is .001.

Any help would be greatly appreciated.



 

the value of p I should use is screwing me up


I'm not sure that I understand this statement's meaning.

Are you telling us that you have the value, but it's not working out in the formula the way you expect?

In any event, we would like to see what you've tried or thought about thus far. Doing that will help make your situation more clear for us.

For additional information, please check our FORUM GUIDELINES.

Cheers :cool:
 
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