Analysis of Variance, or ANOVA, is a statistical method used to compare the means of three or more groups to determine if at least one group mean is significantly different from the others. It helps researchers understand if variations in data are due to different treatments or random chance. ANOVA works by analyzing the variance within each group and between the groups. If the variance between the groups is significantly larger than the variance within the groups, it suggests that the group means are not all equal. This technique is widely used in experiments and studies across various fields.