To test whether people in bars drink more when they are in groups than when they are alone, researchers visited all the pubs in a city. they ordered beers and recorded observations on napkins and pieces of newspaper. why did they keep their identities in disguise?

To test whether people in bars drink more when they are in groups than when they are alone, researchers visited all the pubs in a city. They ordered beers and recorded observations on napkins and pieces of newspaper. They kept their identities in disguise because if they had revealed that their purpose was to conduct an experiment on the behaviors of the people in the bar, it might have triggered that some people changed their usual attitudes.

answer; can each be concretely realized in different ways;

answer; night terrors;