Final answer:
The term used by pollsters for a respondent's purported opinion when they have no view on an issue is a "Don't know response." Scientific polls attempt to minimize inaccuracies from such responses by vetting knowledge with a quiz and reducing sampling errors.
Step-by-step explanation:
The term pollsters use to define a purported opinion offered by a respondent who, in truth, has no view on a specific issue is called a "Don't know response". When respondents are unwilling to admit their lack of knowledge on a polling topic, they might avoid saying "I don't know." This can be problematic as it can introduce inaccuracies in the poll results. To minimize this, pollsters may include a quiz to verify a respondent's knowledge before considering their opinion in the overall survey results. Moreover, a scientific poll aims to create a representative and random sample with lower margins of error, despite challenges like social pressure and human nature that can affect the outcomes.