Such data is called ordinal (see https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_s..

Such data is called ordinal (see https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_s...). You could use arithmetic means etc. if the distance between the categories were equal. Unfortunately, nobody defined what 1, 2, 3 ... stars mean.