P-Value

{
  "id": "MLC-T-ENV-022824",
  "term": "P-Value",
  "field": "Environment",
  "definition": "1. In testing a hypothesis, the probability of a type I error (false positive). The probability that the sample (experimental) results are compatible with a specific hypothesis.\n\n2. In hypothesis testing, the probability that an observed difference between the intervention and control groups is due to chance alone if the null hypothesis is true. If P is less than the α-level (typically 0.01 or 0.05) chosen prior to the study, then the null hypothesis is rejected.\n\n3. A probability calculated from a test statistic; it is the probability of obtaining data at least as extreme as has been obtained if the tested hypothesis were true. [NZ 2002]\n\n4. A measure of the probability that a result happened by chance. The lower the p-value, the more likely it is that the result was caused by phenomenon of interest.\n\n5. The probability value (p-value) of a statistical hypothesis test is the probability of getting a value of the test statistic as extreme as or more extreme than that observed by chance alone, if the null hypothesis H₀, is true. It is the probability of wrongly rejecting the null hypothesis if it is in fact true. It is equal to the significance level of the test for which we would only just reject the null hypothesis. The p-value is compared with the actual significance level of our test and, if it is smaller, the result is significant. That is, if the null hypothesis were to be rejected at the 5% significance level, this would be reported as \"p < 0.05.\" Small p-values suggest that the null hypothesis is unlikely to be true. The smaller it is, the more convincing is the rejection of the null hypothesis. It indicates the strength of evidence for say, rejecting the null hypothesis H₀, rather than simply concluding \"Reject H₀\" or \"Do not reject H₀.\" [STEPS 1997]\n\n6. In hypothesis testing, the probability that an observed difference between the intervention and control groups is due to chance alone if the null hypothesis is true. If P is less than the α-level (typically 0.01 or 0.05) chosen prior to the study, then the null hypothesis is rejected. [NLM/NICHSR 2004]",
  "subject": "Science and research",
  "references": [
    "Benchmark Dose Software (BMDS) Glossary of Terms",
    "NLM/NICHSR 2004",
    "Thesaurus of Terms Used in Microbial Risk Assessment",
    "National Cancer Institute Thesaurus"
  ],
  "url": "https://mlchart.com/terminology/environment/p-value/"
}