귀무가설, or the null hypothesis, is a fundamental concept in statistics. It represents a default position that there is no effect or no difference in a given situation. Researchers use it as a starting point for statistical testing, aiming to determine whether there is enough evidence to reject it in favor of an alternative hypothesis. In hypothesis testing, if the data collected shows a significant effect or difference, the 귀무가설 may be rejected. This process helps scientists and statisticians draw conclusions about their data, guiding decisions in fields like 의학, 심리학, and 사회과학.