Refer to a study described in a Sacramento Bee article titled "Much Ado Over Those Bad Hairdos" (January 26, 2000, p. A21). Here is part of the article:

Researchers surveyed 60 men and 60 women from 17 to 30, most of them Yale students. They were separated into three groups. One group was questioned about times in their lives when they had bad hair. The second group was told to think about bad product packaging, like leaky containers, to get them in a negative mind-set. The third group was not asked to think about anything negative. The groups were tested for self-esteem and self-judgment, and the bad hair group scored lower than the others.

Discuss each of the following "difficulties and disasters" in the context of this research.

a. Ecological validity.

b. Extending results inappropriately.

c. Experimenter effect.