Final Answer:
The type of evidence being used when a speaker mentions "standard advice for impromptu speaking is to keep the speech short, just 1-2 minutes in length" is 2)Expert testimony.
Step-by-step explanation:
Expert testimony refers to information or advice given by individuals who possess authoritative knowledge, skills, or experience in a particular field. In this context, the speaker is providing guidance on impromptu speaking based on their expertise in public speaking or communication. The assertion isn't supported by statistics or a logical argument but rather relies on the speaker's authority or expertise in the subject matter.
This statement isn't based on anecdotal evidence, which typically involves personal stories or isolated instances rather than expert knowledge. It also doesn't rely on statistical evidence, which would present data or figures to support the claim. Additionally, logical reasoning involves constructing a persuasive argument based on premises leading to a conclusion, but the given statement doesn't follow this structure; instead, it appeals to the authority of the speaker in the field of impromptu speaking.
Therefore, the assertion about the recommended duration for impromptu speaking being 1-2 minutes is based on the speaker's expertise in the field, falling under the category of expert testimony rather than statistical evidence, anecdotal evidence, or logical reasoning.correct option is 2)Expert testimony.