# Weighted Means of Subjective Evaluations

• Jaume Casasnovas
• J. Vicente Riera
Chapter
Part of the Studies in Fuzziness and Soft Computing book series (STUDFUZZ, volume 273)

## Abstract

In this article, we recall different student evaluation methods based on fuzzy set theory. The problem arises is the aggregation of this fuzzy information when it is presented as a fuzzy number. Such aggregation problem is becoming present in an increasing number of areas: mathematics, physic, engineering, economy, social sciences, etc. In the previously quoted methods the fuzzy numbers awarded by each evaluator are not directly aggregated. They are previously defuzzycated and then a weighted mean or other type of aggregation function is often applied. Our aim is to aggregate directly the fuzzy awards (expressed as discrete fuzzy numbers) and to get like a fuzzy set (a discrete fuzzy number) resulting from such aggregation, because we think that in the defuzzification process a large amount of information and characteristics are lost. Hence, we propose a theoretical method to build n-dimensional aggregation functions on the set of discrete fuzzy number. Moreover, we propose a method to obtain the group consensus opinion based on discrete fuzzy weighted normed operators.

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