Advertisement: In a carefully controlled study, blindfolded volunteers were divided evenly into five groups  Each volunteer tasted Sparkle Cola and one of five competing colas, each group tasting a different cola  Most of the volunteers said they preferred Sparkle Cola to the competing cola tasted
This shows that Sparkle Cola elicits a more favorable response from consumers than any of the competing colas tested
It overlooks the possibility that a generalization true of the entire group of volunteers was not true of each of the five smaller groups.