probability of obtaining test results at least as extreme as the results actually observed, under the assumption that the null hypothesis is correct
Wikipedia
en.wikipedia.org › wiki › P-value
p-value - Wikipedia
3 weeks ago - In null-hypothesis significance testing, the p-value is the probability of obtaining test results at least as extreme as the result actually observed, under the assumption that the null hypothesis is correct. A very small p-value means that such an extreme observed outcome would be very unlikely ...
Reddit
reddit.com › r/askstatistics › what is p value?
r/AskStatistics on Reddit: What is p value?
August 20, 2024 -
I always get super confused about what the p value is and what it tells us about our hypothesis. Would love to understand how can one interpret it!
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P value is the probably of seeing something at least as extreme as what you have seen (assuming the null hypothesis is true)
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As an example, you have a coin. You assume the coin is fair (NULL HYPOTHESIS). Given the null hypothesis, you expect 50% tails and heads after many many runs of coin tosses. The coin gives you 90% heads (and 10% tails) after a thousand runs of coin tosses. Given you assume that the coin is fair, how much deviation do you accept from the 50/50 situation? Is it okay that 55% are one side for it to still be fair after 1000 tosses? 60%? 70%? P-value is basically the probability of seeing something so extremely deviatiang from the 50/50 that you would still accept the claim that the coins are fair. If you throw the coin 10 times, would you say the coin is fair if 90% of the tosses are heads? What if you throw 100 times and still 90% are heads? A 1000 times? In this example, p-value reflects the probability of witnessing the kind of deviation from 50% heads that you do witness. With 10 tosses it would be small, with a 1000 tosses it would be very very small, again, GIVEN YOU EXPECT 50/50. This is why sample size matters. The p-value tells you how unlikely the observed effect is given what you expect (a 50/50 amount of heads and tails in our case). After 1000 throws, if you assume the outcome should be 50% heads (and tails), receiving 90% heads would be VERY unlikely. P-value would then be the probability of seeing 90% heads given you expect to see 50% heads.
What is p value? : AskStatistics
I always get super confused about what the p value is and what it tells us about our hypothesis. Would love to understand how can one interpret it! More on old.reddit.com
Is a p value of p < 0.024 significant? (Paired samples T-test)
Significance is at whatever p value you want it to be. Cutoff levels vary by field. .05 is used in many disciplines while other disciplines are more stringent.
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August 17, 2016[Q] What does Negative P-Value in Multiple Regression indicate?
If you really have a negative p-value something is broken. However, I expect that what you're looking at isn't a p-value (or just possibly it isn't actually negative, such as if you're looking at a sign on an exponent) More on reddit.com
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July 2, 2020What do p values in baseline characteristics tables mean?
"Significant" or "statistically significant" is an unfortunate, but standard term meaning "we can reject the null hypothesis". Here the null hypothesis is that the mean of the population from which these two groups were drawn are equal; the alternate is that they are not equal, or "there is a difference in the means". "No significant difference" means that since the p values for the hypothesis tests are high, they cannot reject the null that the means are equal. More on reddit.com
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January 24, 2017What does p-value of 0.05 mean?
If your p-value is less than or equal to 0.05 (the significance level), you would conclude that your result is statistically significant.
This means the evidence is strong enough to reject the null hypothesis in favor of the alternative hypothesis.
This means the evidence is strong enough to reject the null hypothesis in favor of the alternative hypothesis.
simplypsychology.org
simplypsychology.org › statistics › understanding p-values and statistical significance
Understanding P-Values and Statistical Significance
How do you calculate a p-value?
P-values are usually automatically calculated by the program you use to perform your statistical test. They can also be estimated using p-value tables for the relevant test statistic. · P-values are calculated from the null distribution of the test statistic. They tell you how often a test statistic is expected to occur under the null hypothesis of the statistical test, based on where it falls in the null distribution. · If the test statistic is far from the mean of the null distribution, then the p-value will be small, showing that the test statistic is not likely to have occurred under the n
scribbr.com
scribbr.com › home › understanding p values | definition and examples
Understanding P-values | Definition and Examples
Can a non-significant p-value indicate that there is no effect or difference in the data?
No, a non-significant p-value does not necessarily indicate that there is no effect or difference in the data. It means that the observed data do not provide strong enough evidence to reject the null hypothesis.
There could still be a real effect or difference, but it might be smaller or more variable than the study was able to detect.
Other factors like sample size, study design, and measurement precision can influence the p-value. It's important to consider the entire body of evidence and not rely solely on p-values when interpreting research findings.
There could still be a real effect or difference, but it might be smaller or more variable than the study was able to detect.
Other factors like sample size, study design, and measurement precision can influence the p-value. It's important to consider the entire body of evidence and not rely solely on p-values when interpreting research findings.
simplypsychology.org
simplypsychology.org › statistics › understanding p-values and statistical significance
Understanding P-Values and Statistical Significance
Videos
WMed
wmed.edu › sites › default › files › P-VALUES SIMPLIFIED.pdf pdf
P-VALUES SIMPLIFIED Preface
Hence, the concept of a p-value concerns the notion of probability. ... The branch of mathematics concerning events and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1 (inclusive).
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5665734
What the P values really tell us - PMC
The P value means the probability, for a given statistical model that, when the null hypothesis is true, the statistical summary would be equal to or more extreme than the actual observed results [2]. Therefore, P values only indicate how incompatible the data are with a specific statistical ...
Investopedia
investopedia.com › terms › p › p-value.asp
P-Value: What It Is, How to Calculate It, and Examples
October 3, 2025 - P-value is the level of marginal significance within a statistical hypothesis test, representing the probability of the occurrence of a given event.
Simply Psychology
simplypsychology.org › statistics › understanding p-values and statistical significance
Understanding P-Values and Statistical Significance
August 11, 2025 - If the null hypothesis is rejected, the alternative becomes the more plausible explanation. A p-value, or probability value, is a number describing how likely it is that your data would have occurred by random chance (i.e., that the null hypothesis ...
Scribbr
scribbr.com › home › understanding p values | definition and examples
Understanding P-values | Definition and Examples
June 22, 2023 - The p value is a number, calculated from a statistical test, that describes how likely you are to have found a particular set of observations if the null
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC4111019
P – VALUE, A TRUE TEST OF STATISTICAL SIGNIFICANCE? A CAUTIONARY NOTE - PMC
This finding will obviously, be welcomed but it is also possible that this finding is purely due to chance. Thus, Fisher saw P value as an index measuring the strength of evidence against the null hypothesis (in our examples, the hypothesis that there is no association between poverty level and malnutrition or the new therapy does not improve nutritional status).
NCBI
ncbi.nlm.nih.gov › books › NBK557421
Hypothesis Testing, P Values, Confidence Intervals, and Significance - StatPearls - NCBI Bookshelf
March 13, 2023 - A research hypothesis is often tested with results provided, typically with p values, confidence intervals, or both. Additionally, the investigators estimate or determine the significance of statistical or research. Unfortunately, healthcare providers may have different comfort levels in ...
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC2895822
In Brief: The P Value: What Is It and What Does It Tell You? - PMC
Thus a p value is simply a measure of the strength of evidence against H0. A study with a p = 0.531 has much less evidence against H0 than a study with a p = 0.058. However, a study with a p = 0.058 provides similar evidence as a study with a p = 0.049 and a study with a p = 0.049 also has much less evidence than one with a p = 0.015.
Amplitude
amplitude.com › explore › experiment › p-values
P Values: What They Are and How to Calculate Them | Amplitude
April 28, 2025 - P-values tell us how likely our results are if there’s no real effect—they measure probability. Confidence intervals, on the other hand, give us a range where the true effect lies. The value is an estimation rather than a set number.
Khan Academy
khanacademy.org › math › ap-statistics › xfb5d8e68:inference-categorical-proportions › idea-significance-tests › v › p-values-and-significance-tests
P-values and significance tests (video)
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Tidsskrift for Den norske legeforening
tidsskriftet.no › en › 2015 › 09 › why-p-value-significant-0
Why the p-value is significant | Tidsskrift for Den norske legeforening
September 8, 2015 - Then a set of mathematical-statistical methods are applied to estimate the probability of what we are observing, given that the null hypothesis is actually correct. The probability of what we are observing or any greater deviations from the null hypothesis – assuming that the null hypothesis is correct – is our p-value.
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5059270
P value interpretations and considerations - PMC
The P value is the probability of rejecting or failing to reject the null hypothesis (H0) (4). H0 is the hypothesis that there is no difference between two groups for a specific variable. The “P” in P value stands for probability. A P value is calculated as the probability that an observed ...
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC4635100
What does the p value really mean? - PMC
Another misconception is that if the p value is greater than 5%, the new treatment has no effect. The p value indicates the probability of observing a difference as large or larger than what was observed, under the null hypothesis.
YouTube
youtube.com › watch
p-value - easily explained with an example - YouTube
What is the p-value and how is it interpreted? That's exactly what you'll learn in this video!The p-value tells us:How likely it is to draw a sample that dev...
Published November 29, 2022
YouTube
youtube.com › statquest with josh starmer
p-values: What they are and how to interpret them - YouTube
This StatQuest is all about interpreting p-values. You've seen them online or in publications, or heard about them, whispered in dark, rave filled dance club...
Published March 22, 2020 Views 205K
StatsDirect
statsdirect.com › help › basics › p_values.htm
P Values (Calculated Probability) and Hypothesis Testing - StatsDirect
The P value or calculated probability is the estimated probability of rejecting the null hypothesis (H0) of a study question when that hypothesis is true.
Springer
link.springer.com › home › european radiology experimental › article
Statistical significance: p value, 0.05 threshold, and applications to radiomics—reasons for a conservative approach | European Radiology Experimental
March 11, 2020 - The p value is probably the most ubiquitous and, at the same time, misunderstood index in all of biomedical research. Hundreds of articles were published on this topic since at least the 1940s [3], with proposals of alternatives to the classic p value with its historical 0.05 threshold.
Numiqo
numiqo.com › tutorial › p-value
p-value: A Beginner’s Guide
October 27, 2025 - We assume that the null hypothesis is true, that is, that there is no difference between the salaries of men and women. In the observed result (sample) we now find out that men earn 150 € more per month than women. The p-value now indicates how likely it is to draw a sample in which the salary of men and women differ by 150€ or more, even though there is no difference in the population.