(06-19-2019, 01:42 PM)flsprtsgod Wrote:

(06-19-2019, 12:31 PM)The Real Marty Wrote: Interesting, but I remember the question from college.  

How large a sample size is necessary for a population of 300 million, to get a confidence level of 95% that your margin of error is 3%?  

https://www.checkmarket.com/sample-size-calculator/

And the answer is, 1,068.   Use the sample size calculator above.  

In fact, 1,068 is a large enough sample size for any size population.  I remember the professor showing us this.  

Of course, the trick is to get a random sample, and that's where the real work comes in, but 1,068 is quite sufficient.

The math is based on random sampling. When you make a thousand calls to the Upper East Side of Manhattan you don't really get that.

You beat me to it.  1068 calls in New York or California isn't going to get the same results as 1068 calls in Texas or Nebraska.

The problem with polling is someone can determine that outcome before it is even conducted based on the question asked and who is asked.  Even if you break it down by county you would get way different results between say Putnam County and Dade County here in Florida.

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