Nulldisztribúció

Nulldisztribúció, also known as the null distribution, is a fundamental concept in statistics and probability theory. It refers to the probability distribution of a test statistic under the assumption that a specific statistical hypothesis is true. This hypothesis is often referred to as the null hypothesis, which typically posits that there is no effect or no difference between groups being compared.

The null distribution is crucial in hypothesis testing, where the goal is to determine whether the observed data provides enough evidence to reject the null hypothesis in favor of an alternative hypothesis. By comparing the test statistic to the null distribution, researchers can calculate a p-value, which indicates the probability of observing a test statistic as extreme as, or more extreme than, the one observed, assuming the null hypothesis is true.

The shape and parameters of the null distribution depend on the specific statistical test being used. For example, in the context of a t-test, the null distribution is often a t-distribution with a specified number of degrees of freedom. In the case of a chi-square test, the null distribution is a chi-square distribution with a specified number of degrees of freedom.

Understanding the null distribution is essential for interpreting the results of statistical tests accurately. It helps researchers to assess the strength of evidence against the null hypothesis and make informed decisions based on the data.