Studying observable characteristics in an audience, such as age, gender, and ethnicity, is known as which of the following?

The correct choice is demographic analysis because it specifically pertains to the examination of audience characteristics that can be quantified, such as age, gender, ethnicity, education level, and income. This type of analysis helps speakers tailor their messages to resonate with the audience's unique traits and backgrounds, which can significantly enhance the effectiveness of communication.

Demographic analysis provides essential insights that enable a speaker to understand who the audience is, allowing for the creation of relatable content that addresses their interests and values. For instance, knowing the age group can guide the choice of language, examples, and references used in a speech.

In contrast, psychological analysis focuses on the audience's attitudes, beliefs, and motivations, which are more abstract and subjective. Economic analysis, on the other hand, would involve assessing factors related to audience members' financial status or economic conditions, while cultural analysis examines the shared beliefs, practices, and values of a particular group. These approaches do not specifically address the observable characteristics that form the basis of demographic analysis. Thus, demographic analysis is the most appropriate term for studying such observable attributes of an audience.