Statistical tests with MUSHRA data

This work raises concerns regarding the statistical analysis of data obtained with the MUSHRA method. There is a widespread tendency to prefer the ANOVA test, which is supported by the recommendation. This work analyses four assumptions underlying the ANOVA tests: interval scale, normality, equal variances and independence. Data were collected from one experiment and one questionnaire. It is found that MUSHRA data tend to violate all of the above assumptions. The consequences of each violation are debated. The violation of multiple assumptions is of concern. The violation of independence of observations leads to the most serious concern. In light of these findings, it is concluded that ANOVA tests have a high likelihood of resulting in type 1 error (false positives) with MUSHRA data and should therefore never be used with this type of data. The paper finishes with a section devoted to statistical recommendations. It is recommended that when using the MUSHRA method, the Wilcoxon or Friedman tests be used. Alternatively, statistical tests based on resampling methods are also appropriate.