Effect Of Outlier On Analysis Of Variance

Author : M. Shafiqur Rahman, Syfun Nahar

Abstract :This article discusses the effect of outliers on the analysis of variance. It is observed that outliers significantly increase the variation within groups, which leads to a significant change to F-statistic and resulting in a Type II error, where the null hypothesis is accepted incorrectly. Outliers significantly affect the P-values derived from ANOVA, potentially leading to misleading significance levels. Outliers violate the basic assumptions of ANOVA that the residuals are normally and independently distributed with mean 0 and constant variance, making the ANOVA results unreliable. One practical example is given

Keywords :Outliers, ANOVA, F-statistic, Type II error, P-values, statistical assumptions

Conference Name :International Conference on Mathematics, Statistics and Financial Economics (ICMSFE-25)

Conference Place Sydney, Australia

Conference Date 5th Jun 2025