A major problem in user studies are high SDs (=standard deviation). People generally experience and perceive things differently. This imposes problems for statistical analysis of user study data, because methods are often based on means, e.g., means comparison (t-test, ANOVA). Consider two cases: participant A gives on a five-point likert scale the rating 5 to a system (maximum), participant B…
Associate Professor (tenure track) at the University of Vaasa, and Adjunct Professor at the Turku School of Economics. Based in Finland.