Final answer:
Suzy's alteration of her questionnaire answer due to discomfort implies a case of Social Desirability Bias, which affects survey validity by causing individuals to provide answers they believe are socially acceptable.
Step-by-step explanation:
When Suzy changes her answer on a questionnaire regarding a sensitive personal topic such as dreams about sex because she feels uncomfortable admitting the truth, this is an example of Social Desirability Bias. This psychological phenomenon occurs when individuals respond to survey questions in a manner they believe will be viewed favorably by others, rather than providing honest and accurate answers. The goal is to conform to social norms and present themselves in the best light possible.
Suzy's behavior reflects a classic case of social desirability bias, as she is influenced by the desire to project a socially acceptable image to the survey conductors or to the public. This bias can significantly affect the validity of survey results, particularly when the topic involves behavior or opinions that are subject to social judgement or norms.