Understanding P-values | p value for t test
Thepvalueisanumber,calculatedfromastatisticaltest,thatdescribeshowlikelyyouaretohavefoundaparticularsetofobservationsifthenullhypothesisweretrue.Pvaluesareusedinhypothesistesting[1]tohelpdecidewhethertorejectthenullhypothesis.Thesmallerthepvalue,themorelikelyyouaretorejectthenullhypothesis.Whatisanullhypothesis?Allstatisticaltestshaveanullhypothesis.[2]Formosttests,thenullhypothesisisthatthereisnorelationshipbetweenyourvariablesofinterestorthatthereisnodifferenceamonggroups.Forexample,inatwo...
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 hypothesis were true.
P values are used in hypothesis testing[1] to help decide whether to reject the null hypothesis. The smaller the p value, the more likely you are to reject the null hypothesis.
What is a null hypothesis?All statistical tests have a null hypothesis. [2]For most tests, the null hypothesis is that there is no relationship between your variables of interest or that there is no difference among groups.
For example, in a two-tailed t test[3], the null hypothesis is that the difference between two groups is zero.
Example: Null and alternative hypothesisYou want to know whether there is a difference in longevity between two groups of mice fed on different diets, diet A and diet B. You can statistically test the difference between these two diets using a two-tailed t test. Null hypothesis (H0...