JFern's "Statistics"

[J. J.]

Again you're wrong, 3 standard deviations is more than 99%.You'tre hopeless confused about the MOE. If I have 1000 people polled, and 94% or 96% support one candidate, that's well outside the margin of error at the 95% level, the 99% level or the 99.9999999999999% level.

JFRAUD, now you are disagreeing with the website I quoted.  That is quote from it.  E-mail the author and tell him he's wrong.  I should warn you that before you do, my of stats textbook says the same thing.

So does the website you quoted:

You must be logged in to read this quote.

http://www.surveysystem.com/sscalc.htm


You reading comprehension skills are the problem. 

When you say something is statistically significant, you do that based upon on poll, typically a sample of 1000 or so. You completely fail to understand statistics if you don't realize that a reasonably sized sample gives statistically significant information. Go ask your statistics 101 teacher about statistical significance of opinion polls.

I can't beleive you haven't admitted that you're wrong yet. This is g pathetic, and a good example of why I hate Republicans. No matter how obvious I made it, they insist I'm wrong. f**ck you all.

What actually is pathetic is that you cannot comprehend what you are reading, even when you link to it as supportive to you postion.  That's why you have earned the name JFRAUD.  It hasn't been limited to this discussion, but it is common to the bulk of your posts, on various subjects.  The positions that you hold don't may you pathetic; that you can't support them is way does.

As both the recently quoted sites state, there is a level certainty, or "confidence level" is not effected by the results.  That you cannot comprehend that, in the face of evidence posted, only illustrates you lack of understanding, and gives increased reasons to doubt anything you say.

[○∙◄☻¥tπ[╪AV┼cVê└]

Again you're wrong, 3 standard deviations is more than 99%.You'tre hopeless confused about the MOE. If I have 1000 people polled, and 94% or 96% support one candidate, that's well outside the margin of error at the 95% level, the 99% level or the 99.9999999999999% level.

JFRAUD, now you are disagreeing with the website I quoted.  That is quote from it.  E-mail the author and tell him he's wrong.  I should warn you that before you do, my of stats textbook says the same thing.

So does the website you quoted:

You must be logged in to read this quote.

http://www.surveysystem.com/sscalc.htm


You reading comprehension skills are the problem. 

When you say something is statistically significant, you do that based upon on poll, typically a sample of 1000 or so. You completely fail to understand statistics if you don't realize that a reasonably sized sample gives statistically significant information. Go ask your statistics 101 teacher about statistical significance of opinion polls.

I can't beleive you haven't admitted that you're wrong yet. This is g pathetic, and a good example of why I hate Republicans. No matter how obvious I made it, they insist I'm wrong. f**ck you all.

What actually is pathetic is that you cannot comprehend what you are reading, even when you link to it as supportive to you postion.  That's why you have earned the name JFRAUD.  It hasn't been limited to this discussion, but it is common to the bulk of your posts, on various subjects.  The positions that you hold don't may you pathetic; that you can't support them is way does.

As both the recently quoted sites state, there is a level certainty, or "confidence level" is not effected by the results.  That you cannot comprehend that, in the face of evidence posted, only illustrates you lack of understanding, and gives increased reasons to doubt anything you say.

How are you so ing stupid? It's an approximation. It doesn't prove that my better approxmation is wrong.  Here do the calculation yourself:


The actual normal density function is 1/sqrt(2*Pi) * e^(-x^2/2). We get the following
1 standard deviation each way gives 68.27%
2 gives 95.44%
3 gives 99.73%
4 gives 99.994%
5 gives 99.99994%
6 gives 99.9999998%

Busted, yet again, you hypocrite.

Anyways, since you claim you can't ever say that a poll shows a significantly signifant difference then you can explain to me what, in J.Idiot land, the pollsters mean by statistical significance. They only have one poll, and they don't know the true population value. I'd love to see you try to explain that one away.

[○∙◄☻¥tπ[╪AV┼cVê└]

Specifically are you saying that Marist polling is wrong? They had a sample of 1009, and they say

The results of the entire survey are statistically significant at ±3%.

http://www.maristpoll.marist.edu/usapolls/hc050308.htm

You've got a lot of explaining to do.

[J. J.]

Specifically are you saying that Marist polling is wrong? They had a sample of 1009, and they say

The results of the entire survey are statistically significant at ±3%.

http://www.maristpoll.marist.edu/usapolls/hc050308.htm

You've got a lot of explaining to do.

JFraud, you moron, that entire poll is based on a confidence level.  I just e-mailed Marist to see what it is.  They also refer to this as "Margin of Error." 

You have a lot of explaining to do.  There are various citations on this thread quoting the difference between confidence level and confidence interval/MOE, including one from a site that you linked to.  They are all saying the same thing.

Why can you not comprehend it?  You are actually disagreeing not with my comments, but the quotes from the sites.  Are you really that stupid?  Do you really think that anyone will believe you over those sites, especially since you said, go to one of them for an explanation?  Is this a matter of your problems with reading comprehension or something else?

[○∙◄☻¥tπ[╪AV┼cVê└]

Specifically are you saying that Marist polling is wrong? They had a sample of 1009, and they say

The results of the entire survey are statistically significant at ±3%.

http://www.maristpoll.marist.edu/usapolls/hc050308.htm

You've got a lot of explaining to do.

JFraud, you moron, that entire poll is based on a confidence level.  I just e-mailed Marist to see what it is.  They also refer to this as "Margin of Error." 

You have a lot of explaining to do.  There are various citations on this thread quoting the difference between confidence level and confidence interval/MOE, including one from a site that you linked to.  They are all saying the same thing.

Why can you not comprehend it?  You are actually disagreeing not with my comments, but the quotes from the sites.  Are you really that stupid?  Do you really think that anyone will believe you over those sites, especially since you said, go to one of them for an explanation?  Is this a matter of your problems with reading comprehension or something else?

Umm, that's exactly what I said. You have a 95% confidence interval, which has a radius of about 3% for your standard sample of 1000 or so.  If that confidence interval doesn't include a tie, then the lead is  statistically significant. What part of that don't you understand?

I think a brick wall would have understood this by now.

[○∙◄☻¥tπ[╪AV┼cVê└]

I noticed you ignored my comment pointing out that you are yet again a lying hypocrite for telling me that the 95% confidence interval radius is 2, not 1.96 standard deviations.

Not that you being a lying hypocrite is anything new.  When will you ever admit that you're wrong?

[J. J.]

Umm, that's exactly what I said. You have a 95% confidence interval, which has a radius of about 3% for your standard sample of 1000 or so.  If that confidence interval doesn't include a tie, then the lead is  statistically significant. What part of that don't you understand?

I think a brick wall would have understood this by now.

You still have it wrong JFRAUD.  I'm going to go back and quote something I said previously.

You are looking at one poll and assuming that the poll is one of the 19 that is correct, and your basing that on the numbers within that poll.  The results of the poll have no effect on if the sample was an "accurate" sample.  The results do effect MOE, but the only conclusion that can be reached is that Kerry is 95% likely to have support within the MOE.

Now that said, the MOE will be smaller as the support for one cadidate moves away from 50%, but that has nothing to do with if the 95% likelihood that the poll is correct.  For example, if 100 people were polled, we could say that we are 95% confident that Kerry has 94% +/- 4.65%.  Likewise, if 100,000 were polled we could say that we are 95% that Kerry has 94 +/- 0.47%.

If the numbers change the MOE changes.  Assume that Kerry has 40% of the vote, according to the poll.  If 100 people were polled we could say that we are 95% confident that Kerry has 40% +/- 9.6%.  If 100,000 were polled we could say that we are 95% confident that Kerry has 40% +/- 0.3%.

You'll note that in all cases the confidence level stays the same.  None of this affects the confidence level, only makes the MOE shrink or grow.

You are going to be able to determine the confidence level from the results of the single pole.  That is why your basic question illustrates your ignorence of the subject.  You cannot determine if this one of those randomly wrong polls from the internal numbers (though it will effect MOE).

The MOE can change because of the result; that however does not change the confidence level.  It is possible that both candidates will be within the MOE on a given poll, but even in that case there is still a "bad" sample.  The MOE has no effect on determining if the sample is bad.  A 3% MOE does not mean that the sample has a 3% chance of being wrong; it means that if the sample is an accurate representation of the population the candidates score is +/- 3% of the number predicted in the poll.

Example:  Poll #1  Sample size of 1000.  The confidence level is 95%, and the MOE +/- 3.1%, and  Candidate A scores 50%.  The poll (or more accurately the pollster) can say that he is 95% sure that Candidate A has between 46.9% and 53.1% of the vote.  

Poll #2 Now, as stated (and this is hypothetical) that a second poll is conducted, using the same methods, sample size, and at the same time (SMST)  and Candidate A has 90%.  The MOE will drop to +/- 1.86%.  The same pollster can say that he is 95% sure that Candidate A has between 88.14% and 91.86% of the vote.  Nothing has changed in the pollsters methods, it's just a different sample.

Now let's that he takes a total of 20 polls (SMST):

Poll Numbers 1, 3, 4, 5,  Candidate A at 50%  MOE 3.1
Poll Number  2 Candidate A at 90%  MOE 1.86
Poll Numbers 8, 9, 10, 11, Candidate A at 49% MOE 3.1
Poll Numbers 6, 12, 13, 14, Candidate A at 51% MOE 3.1
Poll Numbers 15, 16, 17, Candidate A at 52%   MOE 3.1
Poll Numbers 18, 19, 20 Candidate A at 48%  MOE 3.1

Even though Poll #2 has a lower MOE, it is not an accurate desciption of the electorate.  The pollster could still say that, based on Poll # 2, that he is is 95% sure that Candidate A has between 88.14% and 91.86% of the vote.

Based on your example, there is nothing internal to the poll to show that this isn't a bad poll, like Poll #2; there isn't any way to do that, based on just one poll.  MOE does not come into play in determining this.

[○∙◄☻¥tπ[╪AV┼cVê└]

Umm, that's exactly what I said. You have a 95% confidence interval, which has a radius of about 3% for your standard sample of 1000 or so.  If that confidence interval doesn't include a tie, then the lead is  statistically significant. What part of that don't you understand?

I think a brick wall would have understood this by now.

You still have it wrong JFRAUD.  I'm going to go back and quote something I said previously.

You are looking at one poll and assuming that the poll is one of the 19 that is correct, and your basing that on the numbers within that poll.  The results of the poll have no effect on if the sample was an "accurate" sample.  The results do effect MOE, but the only conclusion that can be reached is that Kerry is 95% likely to have support within the MOE.

Now that said, the MOE will be smaller as the support for one cadidate moves away from 50%, but that has nothing to do with if the 95% likelihood that the poll is correct.  For example, if 100 people were polled, we could say that we are 95% confident that Kerry has 94% +/- 4.65%.  Likewise, if 100,000 were polled we could say that we are 95% that Kerry has 94 +/- 0.47%.

If the numbers change the MOE changes.  Assume that Kerry has 40% of the vote, according to the poll.  If 100 people were polled we could say that we are 95% confident that Kerry has 40% +/- 9.6%.  If 100,000 were polled we could say that we are 95% confident that Kerry has 40% +/- 0.3%.

You'll note that in all cases the confidence level stays the same.  None of this affects the confidence level, only makes the MOE shrink or grow.

You are going to be able to determine the confidence level from the results of the single pole.  That is why your basic question illustrates your ignorence of the subject.  You cannot determine if this one of those randomly wrong polls from the internal numbers (though it will effect MOE).

The MOE can change because of the result; that however does not change the confidence level.  It is possible that both candidates will be within the MOE on a given poll, but even in that case there is still a "bad" sample.  The MOE has no effect on determining if the sample is bad.  A 3% MOE does not mean that the sample has a 3% chance of being wrong; it means that if the sample is an accurate representation of the population the candidates score is +/- 3% of the number predicted in the poll.

Example:  Poll #1  Sample size of 1000.  The confidence level is 95%, and the MOE +/- 3.1%, and  Candidate A scores 50%.  The poll (or more accurately the pollster) can say that he is 95% sure that Candidate A has between 46.9% and 53.1% of the vote. 

Poll #2 Now, as stated (and this is hypothetical) that a second poll is conducted, using the same methods, sample size, and at the same time (SMST)  and Candidate A has 90%.  The MOE will drop to +/- 1.86%.  The same pollster can say that he is 95% sure that Candidate A has between 88.14% and 91.86% of the vote.  Nothing has changed in the pollsters methods, it's just a different sample.

Now let's that he takes a total of 20 polls (SMST):

Poll Numbers 1, 3, 4, 5,  Candidate A at 50%  MOE 3.1
Poll Number  2 Candidate A at 90%  MOE 1.86
Poll Numbers 8, 9, 10, 11, Candidate A at 49% MOE 3.1
Poll Numbers 6, 12, 13, 14, Candidate A at 51% MOE 3.1
Poll Numbers 15, 16, 17, Candidate A at 52%   MOE 3.1
Poll Numbers 18, 19, 20 Candidate A at 48%  MOE 3.1

Even though Poll #2 has a lower MOE, it is not an accurate desciption of the electorate.  The pollster could still say that, based on Poll # 2, that he is is 95% sure that Candidate A has between 88.14% and 91.86% of the vote.

Based on your example, there is nothing internal to the poll to show that this isn't a bad poll, like Poll #2; there isn't any way to do that, based on just one poll.  MOE does not come into play in determining this.

OK, now you're trying a new strategy, say some stuff that is actually right, and then say something wrong and claim that's what I said. when did I say there was ever a 3% probability of something with a 3% MOE?

I see you now know what a confidence interval is. Now, if you have one poll, with a MOE of 3.1% at at the 95% confidence level, and it has Kerry out of that [46.9%, 53.1%] confidence interval, then you can conclude that Kerry has a statistically significant lead (or Bush does), assuming Bush+Kerry=100%. It's statistically significant at that 95% cofidence level. Your probability of falsely rejecting the null hypothesis of a tie is at most p=5%.

[J. J.]

I noticed you ignored my comment pointing out that you are yet again a lying hypocrite for telling me that the 95% confidence interval radius is 2, not 1.96 standard deviations.

Not that you being a lying hypocrite is anything new.  When will you ever admit that you're wrong?

Actually because, as pointed out, you were referring to a statistics website that I quoted.  I pointed that out earlier

You've said quite a lot that bears little resemblence to fact, the earliest one that I recall being your call for a "civil war" and most recent claim that something that happend in July of 1933 triggered something that happened March of 1933 (I'm still wondering where the Vatican keeps it time machine).  You've said so little that is accurate, very little of what you say will be believed.  Of course, when you post links, people do read them, and unlike you, they do understand them.

That's possibly why more and more people are calling you JFRAUD.  It doesn't descibe your politics by qualities of the mental processes as illustrated in your post.

[J. J.]

OK, now you're trying a new strategy, say some stuff that is actually right, and then say something wrong and claim that's what I said. when did I say there was ever a 3% probability of something with a 3% MOE?

I see you now know what a confidence interval is. Now, if you have one poll, with a MOE of 3.1% at at the 95% confidence level, and it has Kerry out of that [46.9%, 53.1%] confidence interval, then you can conclude that Kerry has a statistically significant lead (or Bush does), assuming Bush+Kerry=100%. It's statistically significant at that 95% cofidence level. Your probability of falsely rejecting the null hypothesis of a tie is at most p=5%.

You really do have a problem with reading comprehension.  Here is what was posted two days ago:

The thing is, even if the pollster does everything right, he's still going to get one absolutely wrong result out of the margin of error in X amount of polls.  Now, with a sample size of 1000, X will be lower than if the sample size is 300, but it's still going to happen.

Yeah, well he's never going to get 94-6 with a sample of 1000 when it was really a tie, and that's why 94-6 is a very statistically significant lead.

That you cannot say, statistically.

We are not referring to margin of error directly, but a problem that the poll will just be wrong.   When at a poll, statistically, it is accurate to say, this is the corect number, within the margin of error, X number of times out of 100.  X is usually 95 to 99.

With a 1000 sample poll, the margin of error is always less than 1.582%.
We have 96-4, which is a z-score of 27.8.

If you know anything about z-scores you'll realize there's no way you'll ever get that.

You'll note that I was saying thing then as now.  Now I know you have problems with calendars, but April 24 comes before April 26. (Well, GHW Bush thought September was December in 1988.)  Also note that the just contradicted yourself on that last statement about MOE.

You cannot tell if a poll represents the population from the internal numbers of the poll.  If the example was 50/50, 60/40, or 99/1, you'd still have the same problem.  The only thing the first example you posted showed was that the results were outside of the MOE; that alone does not determine statistical validity. If there more central tendency in the population than in the poll, you will actually get a smaller MOE the more inaccurate the poll is.

[○∙◄☻¥tπ[╪AV┼cVê└]

OK, now you're trying a new strategy, say some stuff that is actually right, and then say something wrong and claim that's what I said. when did I say there was ever a 3% probability of something with a 3% MOE?

I see you now know what a confidence interval is. Now, if you have one poll, with a MOE of 3.1% at at the 95% confidence level, and it has Kerry out of that [46.9%, 53.1%] confidence interval, then you can conclude that Kerry has a statistically significant lead (or Bush does), assuming Bush+Kerry=100%. It's statistically significant at that 95% cofidence level. Your probability of falsely rejecting the null hypothesis of a tie is at most p=5%.

You really do have a problem with reading comprehension.  Here is what was posted two days ago:

The thing is, even if the pollster does everything right, he's still going to get one absolutely wrong result out of the margin of error in X amount of polls.  Now, with a sample size of 1000, X will be lower than if the sample size is 300, but it's still going to happen.

Yeah, well he's never going to get 94-6 with a sample of 1000 when it was really a tie, and that's why 94-6 is a very statistically significant lead.

That you cannot say, statistically.

We are not referring to margin of error directly, but a problem that the poll will just be wrong.   When at a poll, statistically, it is accurate to say, this is the corect number, within the margin of error, X number of times out of 100.  X is usually 95 to 99.

With a 1000 sample poll, the margin of error is always less than 1.582%.
We have 96-4, which is a z-score of 27.8.

If you know anything about z-scores you'll realize there's no way you'll ever get that.

You'll note that I was saying thing then as now.  Now I know you have problems with calendars, but April 24 comes before April 26. (Well, GHW Bush thought September was December in 1988.)  Also note that the just contradicted yourself on that last statement about MOE.

You cannot tell if a poll represents the population from the internal numbers of the poll.  If the example was 50/50, 60/40, or 99/1, you'd still same problem.  The only thing the first example you posted showed was that the results were outside of the MOE; that alone does not determine statistical validity. If there more central tendency in the population than in the poll, you will actually get a smaller MOE the more inaccurate the poll is.

So I meant standard deviation. It would have been the MOE for a 68.27% confidence interval. I didn't say anything about the level of confidence there. You have yet to respond to the following:
I pointed out you were wrong about saying I was wrong about MOE=1.96 standard deviations - no reply
I asked you why they say that a poll of 1000 says

You must be logged in to read this quote.

- no reply

Are you ever going to admit you're wrong?

[J. J.]

So I meant standard deviation. It would have been the MOE for a 68.27% confidence interval. I didn't say anything about the level of confidence there. You have yet to respond to the following:
I pointed out you were wrong about saying I was wrong about MOE=1.96 standard deviations - no reply
I asked you why they say that a poll of 1000 says

You must be logged in to read this quote.

- no reply

Are you ever going to admit you're wrong?

MOE does not = 1.96 SD.  MOE, also known as confidence interval, is function of sample size confidence Level (which is standard deviation), sample size, and poll results.  Here is the description, again, not you have the mentality to comprehend it:

You must be logged in to read this quote.

http://www.surveysystem.com/sscalc.htm

BTW:  This is from the site you used as your source.

As pointed out befor the +/- 3 does not have any bearing on the validity of the poll, as has been pointed out.

You just illustrated your ignorance again. 

Jfern, this is not sarcasm, but you obviously have a reading comprehesion problem at the very least.  I'm not the only one who has noticed it.  You need help.

[○∙◄☻¥tπ[╪AV┼cVê└]

So I meant standard deviation. It would have been the MOE for a 68.27% confidence interval. I didn't say anything about the level of confidence there. You have yet to respond to the following:
I pointed out you were wrong about saying I was wrong about MOE=1.96 standard deviations - no reply
I asked you why they say that a poll of 1000 says

You must be logged in to read this quote.

- no reply

Are you ever going to admit you're wrong?

MOE does not = 1.96 SD.  MOE, also known as confidence interval, is function of sample size confidence Level (which is standard deviation), sample size, and poll results.  Here is the description, again, not you have the mentality to comprehend it:

You must be logged in to read this quote.

http://www.surveysystem.com/sscalc.htm

BTW:  This is from the site you used as your source.

As pointed out befor the +/- 3 does not have any bearing on the validity of the poll, as has been pointed out.

You just illustrated your ignorance again. 

Jfern, this is not sarcasm, but you obviously have a reading comprehesion problem at the very least.  I'm not the only one who has noticed it.  You need help.

If the sample is large, we do the normal approximation. If we want a 95% confidence level, we get a MOE of 1.96 standard deviations. I've gone over this a zillion times. Do you understand now?

You ing need help. How does talking about a MOE of 4 give any new insight?

Here let's dumb it down for you, J Idiot. Kerry is leading Bush 54%-46%. Our sample size is n=1000. Got it? Yeah, I know it's complicated. Now here is a calculator to find if it's statistically significant at the 95% confidence level.
http://americanresearchgroup.com/moe2.shtml

Type in Candidate A: 54%
Candidate B: 46%
Sample Size: 1000

Hit Calculate limits
It says Upper limit: 14.2, lower limit 1.8.

Now at the bottom it says that if the lower limit is positive, the leading candidate has a statistically significant lead over his opponent in that poll.

Now, if J. Idiot has figured that out, he can enter in a 53%-47% lead, and find that it's barely not statistically significant.

[○∙◄☻¥tπ[╪AV┼cVê└]

Have I dumbed it down enough for J. Idiot?

BTW, it doesn't work for small samples.

[J. J.]

If the sample is large, we do the normal approximation. If we want a 95% confidence level, we get a MOE of 1.96 standard deviations. I've gone over this a zillion times. Do you understand now?

I understand that you have no understanding of statistics.

Here is a relatively straight forward explanation of where standard deviation comes into play in determining the confidence level:

You must be logged in to read this quote.

http://encyclopedia.learnthis.info/s/st/standard_deviation_1.html

You've made the claim that "If we want a 95% confidence level, we get a MOE of 1.96 standard deviations. "  Instead of posting this nonsense, why don't you link to a site that says this, and post this statement.

Now the site you just linked to says this:

You must be logged in to read this quote.

As has been explained, the confidence interval is another name for the MOE.  This calculates the MOE.  As has been shown, the MOE does not determine the validity of the poll.  A candidate can have a lead over his opponent well beyond the MOE and the poll can still be invalid.

The statement that a poll shows that cadidate A has a given within the MOE, at a particular Confidence Level, is an accurate statement without regard to what the score is.

[○∙◄☻¥tπ[╪AV┼cVê└]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

[ATFFL]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

[J. J.]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

JFraud there is nothing on that website  that says, as you claim:

If the sample is large, we do the normal approximation. If we want a 95% confidence level, we get a MOE of 1.96 standard deviations. I've gone over this a zillion times.

You said it for "a zillion times" and a zillion times, you have it wrong, or at least you didn't cite it.

Tedrick, you've hit the correct point.  The MOE doesn't show anything about the sample size or the confidence level.

JFRAUD ttpically gets his facts wrong the gets angry when he's called one it.  For him that is typical, typical, typical.

[○∙◄☻¥tπ[╪AV┼cVê└]

http://americanresearchgroup.com/moe2.shtml

That website uses the term statistically significant lead that you argue against. In addition, if you view the source of the webpage, you'll see that it uses 1.96.

[○∙◄☻¥tπ[╪AV┼cVê└]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

It only works if you assume a random sample.

[ATFFL]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

It only works if you assume a random sample.

I thought the goal was to get a randomly selected representative sample.  If I poll a random selection of 1000 Massachusetts Dems and get a 96-4% result it may be statistically significant and completely useless.

[○∙◄☻¥tπ[╪AV┼cVê└]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

It only works if you assume a random sample.

I thought the goal was to get a randomly selected representative sample.  If I poll a random selection of 1000 Massachusetts Dems and get a 96-4% result it may be statistically significant and completely useless.

Well, a random sample is usually pretty representative.

[ATFFL]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

It only works if you assume a random sample.

I thought the goal was to get a randomly selected representative sample.  If I poll a random selection of 1000 Massachusetts Dems and get a 96-4% result it may be statistically significant and completely useless.

Well, a random sample is usually pretty representative.

But not always.  That is why we do validity checks.  Would you accept my above poll as representative of the nation?  Even if they were somehow chosen randomly from the entire US population?

Even if you get the random representative sample there is still a chance that reality is outside of your Margin of Error.  If you do not have a proper sample to begin with, you have error on top of error.  Sometimes two wrongs do make a right, but not usually.

[○∙◄☻¥tπ[╪AV┼cVê└]

That calculator uses 1.96 standard deviations for its 95% confidence interval. Look at the source if you don't believe me. I see you haven't gone to that website, you g fraud. 

You didn't quote the part where I talked about this link. I bet you hope this site will go away. Sorry, it doesn't work that way.
http://americanresearchgroup.com/moe2.shtml

J. Idiot., you lose. Argument over.

Quick question:  How does that calculator help if the sample is not a representation of the public at large?

It only works if you assume a random sample.

I thought the goal was to get a randomly selected representative sample.  If I poll a random selection of 1000 Massachusetts Dems and get a 96-4% result it may be statistically significant and completely useless.

Well, a random sample is usually pretty representative.

But not always.  That is why we do validity checks.  Would you accept my above poll as representative of the nation?  Even if they were somehow chosen randomly from the entire US population?

Even if you get the random representative sample there is still a chance that reality is outside of your Margin of Error.  If you do not have a proper sample to begin with, you have error on top of error.  Sometimes two wrongs do make a right, but not usually.

You're asking for a weighted random sample. That would be less random then a random sample. If you knew you had the true weight (let's say 35% Dem, 35% GOP, 30% Indepdendent, or something, I made those numbers up), then you can calculate the MOE on each part equally, and find the combined MOE weigted MOE, by finding the MOE of each subsample, and adding them using the Pythagorean formula for adding standard deviations.  Then, that would give you a smaller MOE, but it's not what I was talking about because didn't want to get into complicated matters like weighted non-random polls.

[ATFFL]

You're asking for a weighted random sample. That would be less random then a random sample. If you knew you had the true weight (let's say 35% Dem, 35% GOP, 30% Indepdendent, or something, I made those numbers up), then you can calculate the MOE on each part equally, and find the combined MOE weigted MOE, by finding the MOE of each subsample, and adding them using the Pythagorean formula for adding standard deviations.  Then, that would give you a smaller MOE, but it's not what I was talking about because didn't want to get into complicated matters like weighted non-random polls.

No, weighting is not the same thing as I am talking about.  I am talking about validity checks.

Simple question:  Is a poll of 1000 registered Democrats livining in Boston representative of the general electorate?

Random samples can and  blow up.  They can pull in far too many members of any group.  We know from the census that the US population has 12.9% African Americans.  Let's say that If a poll gets 20% African American respondednts that is too much for the nation.  We can either weight it down to a more reasonable amount, increase our sample size by interviewing people of other ethnic groups, toss the poll out and start over or, if we are irresponsible, release it and pretend it is a propre representative sample.

If we get a poll that is 14% African American we can weight it down, or leave it be since it is close enough.

A poll can be picture perfect, spot on for every measurable demographic and perfect in every technical aspect with questions that are perfectly neutral and readers who show no prejudice one way or another and still be completely wrong.