A revolution in thought

[Spacemonkey]

Originally Posted by But

So what is the probability?

Have you not been paying attention, But? It is small and strong!

[Florence Jellem]

Originally Posted by But

So what is the probability?

You might as well ask the poor ditz, "Kenneth, what is the frequency?"

[peacegirl]

Originally Posted by But

So what is the probability?

I answered your question. The P-value that is <5 is considered statistically significant and not derived from chance. But there is a lot of controversy as to whether the P-value brings us any closer to the truth, which is the whole point.

[Spacemonkey]

Originally Posted by Spacemonkey

Well, look at that. You're evading again! Two questions there and you didn't even try to answer either of them.

How are we going to be able to see a supernova in real time if light from it first has to arrive at the eye?

So how does the light from the supernova get to the distant eye in zero time without violating the laws of physics?

It's already easy for me. I just don't get why you post nonsense and then ask us not to respond. If you want to post without replies then go start a blog. This is a discussion forum - people can and will respond.

Another lie. You've admitted defeat several times already. If you want to try something new, try honestly and directly answering questions.

Bump for PG.

[But]

Originally Posted by peacegirl

I answered your question.

No, you didn't. A probability is a number between 0 and 1. If the p-value is 0.02, what is the probability that the results are obtained assuming the null hypothesis is true?

[The Lone Ranger]

Originally Posted by peacegirl

According to the P-value of .02, there is a strong probability that the results are significant, but there are times when the P-value to be misleading.

Oh gods, the stupidity/ignorance, it burns!

Why on earth do you insist upon blathering on about things that you clearly don't understand in the slightest?



That's a rhetorical question, by the way. [Look it up.]

[Vivisectus]

I wonder if dogs can see a supernova

[Dragar]

Why can't you just admit you don't know anything about statistics or p-values, peacegirl?

Most people don't know about these things. They are quite technical points.

Most people don't try to fool others (particularly so badly!) that they do know something.

[peacegirl]

Originally Posted by But

No, you didn't. A probability is a number between 0 and 1. If the p-value is 0.02, what is the probability that the results are obtained assuming the null hypothesis is true?

The choice of significance level at which you reject H0 is arbitrary. Conventionally the 5% (less than 1 in 20 chance of being wrong), 1% and 0.1% (P < 0.05, 0.01 and 0.001) levels have been used. These numbers can give a false sense of security.

In the ideal world, we would be able to define a "perfectly" random sample, the most appropriate test and one definitive conclusion. We simply cannot. What we can do is try to optimise all stages of our research to minimise sources of uncertainty. When presenting P values some groups find it helpful to use the asterisk rating system as well as quoting the P value:

P < 0.05 *

P < 0.01 **

P < 0.001



Most authors refer to statistically significant as P < 0.05 and statistically highly significant as P < 0.001 (less than one in a thousand chance of being wrong).

P Values (Calculated Probability) and Hypothesis Testing - StatsDirect

[Spacemonkey]

Why can't you just admit it when you don't understand something?

You're making yourself look ridiculous.

[peacegirl]

Originally Posted by Spacemonkey

Why can't you just admit it when you don't understand something?

You're making yourself look ridiculous.

Why Are P Values Misinterpreted So Frequently?
July 31, 2017 By Jim Frost

P values are commonly misinterpreted. It’s a very slippery concept that requires a lot of background knowledge to understand. Not surprisingly, I’ve received many questions about P values in statistical hypothesis testing over the years. However, one question stands out. Why are P value misinterpretations so prevalent? I answer that question in this blog post, and help you avoid making the same mistakes.

cont. at: Why Are P Values Misinterpreted So Frequently? - Statistics By Jim

[But]

That's all great and good, but what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

[peacegirl]

Originally Posted by But

That's all great and good, but what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

P-values are most likely to be near 0 if the alternative hypothesis holds

Approximately 50% of p-values are less than 0.5, 20% are less than 0.2, etc. when the null hypothesis is true.

Interpretation of p-value

Remembering that low p-values favour HA more than H0, we can give the following interpretation to a p-value.

If a data set gives rise to a p-value of say 0.0023, we can state that the probability of getting a data set with such a low p-value is only 0.0023 if H0 is true. Since such a low p-value is so unlikely, the data give strong evidence that H0 does not hold.

Of course, we may be wrong. A p-value of 0.0023 could arise when either H0 or HA holds. However it is unlikely when H0 is true and more likely when HA is true.

Similarly, p-value that is as low as 0.4 occurs with probability 0.4 when the null hypothesis holds. Since this is fairly high, we conclude from a data set that gave rise to a p-value of 0.4 that there is no evidence that the null hypothesis does not hold.

Although it may be regarded as an over-simplification, the table below may be used as a guide to interpreting p-values.

p-value Interpretation

over 0.1 no evidence that the null hypothesis does not hold

between 0.05 and 0.1 very weak evidence that the null hypothesis does not hold

between 0.01 and 0.05 moderately strong evidence that the null hypothesis does not hold

under 0.01 strong evidence that the null hypothesis does not hold

[But]

Great copypaste. Now what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

[peacegirl]

Originally Posted by But

Great copypaste. Now what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

I'm done discussing P-values with you. As far as the statistical significance of the one experiment you linked me to that even comes close to what you were looking for (i.e., that dogs are able to recognize their master by sight alone), has not even come close to the reality that dogs can actually do this, regardless of what the P-value suggests. Furthermore, the experiment you used to discredit Lessans' claim did not test the actual claim, and they certainly did not prove their case by suggesting that a 4 second glance at the human face was proof of true recognition.

[specious_reasons]

Originally Posted by peacegirl

Furthermore, the experiment you used to discredit Lessans' claim did not test the actual claim, and they certainly did not prove their case by suggesting that a 4 second glance at the human face was proof of true recognition.

[But]

Originally Posted by peacegirl

I'm done discussing P-values with you.

And still no answer. You just can't admit that you don't understand it, can you? It's pathetic.

[peacegirl]

Originally Posted by But

And still no answer. You just can't admit that you don't understand it, can you? It's pathetic.

The p-value as a percentage, ie. p-value of 0.05 =5%. p-value of 0.13 = 13%, p-value of 0.02 = 2%. The p-value is then the percentage chance (2% in this case) of being wrong if you reject the null. Am I right? It doesn't matter. I'M DONE DISCUSSING THIS WITH YOU! You think this somehow is proof that Lessans was wrong. Have you ever seen a dog get excited seeing his master (that he has not seen in months) on a computer screen with no other sensory cues? No! Why don't they do this kind of experiment? You know why? Because it would disprove their hypothesis, and who wants that when a P-value can prove that they're hypothesis was statistically significant with a small error rate?

[Stephen Maturin]

Originally Posted by Vivisectus

I wonder if dogs can see a supernova

It's a closed system, V. Just picture a really, really long dog house with Pickles the Schnauzer at one end and a supernova at the other. A mirror image is, of course, instantly at Pickles' retina. However, poor Pickles is unable to identify what he is efferently viewing, because dogs cannot recognize supernovae by sight alone. If Pickles recognizes what he's seeing as a supernova, it would be because of the supernova's gait or some other clue. The problem, ya see, is that dogs cannot project words onto screens of undeniable substance.

Seriously, you guys, how many times must I explain this stuff? If you can't get it, oh well. It's fine with me if you think Lessans did not make a discovery, and I certainly won't be spending the next 7+ years revisiting the issue over and over.

[But]

OK, so what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

[peacegirl]

Originally Posted by But

OK, so what's the probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis?

If you want to explain something to me that you think I've missed, then do it. Stop quizzing me.

[peacegirl]

Originally Posted by Stephen Maturin

It's a closed system, V. Just picture a really, really long dog house with Pickles the Schnauzer at one end and a supernova at the other. A mirror image is, of course, instantly at Pickles' retina. However, poor Pickles is unable to identify what he is efferently viewing, because dogs cannot recognize supernovae by sight alone. If Pickles recognizes what he's seeing as a supernova, it would be because of the supernova's gait or some other clue. The problem, ya see, is that dogs cannot project words onto screens of undeniable substance.

Seriously, you guys, how many times must I explain this stuff? If you can't get it, oh well. It's fine with me if you think Lessans did not make a discovery, and I certainly won't be spending the next 7+ years revisiting the issue over and over.

It doesn't take a lot of smarts to make fun of someone than to actually understand what he's saying. Obviously you don't and you never did. This says more about you than anyone else.

[But]

Originally Posted by peacegirl

If you want to explain something to me that you think I've missed, then do it. Stop quizzing me.

Missed? You haven't answered the question.

[peacegirl]

Originally Posted by But

Missed? You haven't answered the question.

The probability, if the p-value is 0.02, that you would get a result that's just as strong under the null hypothesis cannot be determined from one experiment. The strength of a result would be dependent on further experiments to either add supporting evidence (Ho) or not. If that's wrong, then I don't understand the question. You'll have to explain. After that, I'm done discussing p-values, because none of these experiments are foolproof, nor do they in any way negate his claim that dogs cannot recognize familiar faces from sight alone.

[Florence Jellem]

Boys, let’s also not forget that a supernova is much closer than scientists assume, in the experiments they conduct that are designed to confirm their own assumptions (this is called “bias confirmaton” and “logic chopping,” in case you didn’t know.) A supernova may only be ten feet away or so, in which case it will certainly be big enough and bright enough for Pickles to see it, meeting the conditions of efferent vision. However, as that nice Mr. Maturin points out, Pickles will not be able to recognize the supernova by sight alone, but will have to pick up its gait or perhaps its odor. One must not forget, also, that the inverse square law is involved in all of this, as is, crucially, the p-value, but we are not going to discuss the p-value any longer.