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Let's clear up misinformation about Polling Margin of Error [View All]

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TruthIsAll Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Nov-17-04 10:02 PM
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Let's clear up misinformation about Polling Margin of Error
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Edited on Wed Nov-17-04 10:04 PM by TruthIsAll
Let's clear up misinformation about Polling Margin of Error.

The greater the sample size the more accurate the estimate,
since the MoE decreases as the sample size increases. 

The MoE is equal to 1.96 * the standard deviation (Stdev)
The Stdev is a measure of dispersion around the sample mean.  

A typical national poll samples 1000-1200.

It makes NO difference whether one is sampling a city,  state
or the nation. The ONLY thing that matters is the number of
people sampled, not the SIZE of the underlying population
(city, state, or nation).

Exit Polls taken are more accurate than standard polls.
The exit polls sampled more than 2000 people in the critical
states.
An exit poll of 2000 people has an MoE of LESS than one
percent.

The statistics supplied below are applicable to STANDARD
pre-election polls. 

For any sample size, the sample mean will be within the MoE of
the actual population mean 95% of the time.

For a 1000 sample size, the sample mean will be within 3.10%
of the actual mean 95% of the time.

For a 2000 sample size, the sample mean will be within 2.19%
of the actual mean 95% of the time.

And so on...


Sample	Sample	Std
Size	MoE	Dev

1000 	3.10%	1.58%
1250 	2.77%	1.41%
1500 	2.53%	1.29%
2000 	2.19%	1.12%
3000 	1.79%	0.91%
		
4000 	1.55%	0.79%
5000 	1.39%	0.71%
6000 	1.27%	0.65%
7000 	1.17%	0.60%
8000 	1.10%	0.56%
		
9000 	1.03%	0.53%
10000 	0.98%	0.50%
11000 	0.93%	0.48%
12000 	0.89%	0.46%
13000 	0.86%	0.44%
		
14000 	0.83%	0.42%
15000 	0.80%	0.41%
16000 	0.77%	0.40%
17000 	0.75%	0.38%
18000 	0.73%	0.37%
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