No, 0.05$ is not a substantial amount of money. A 5 percentage points tax increase could be considered substantial. The question is worded so that it can be interpreted in the latter way, and it’s also using a subjective word like “substantial”. Somebody who is politically against taxes is likely to interpret it the latter way, and hence the poll’s results are skewed by its vagueness.
If we want to measure math skills and understanding of the law, a better question would be by how many dollars the total tax would increase. This would also give us better information on how far off people are.
Please, you’re wasting your time explaining. I know all this. I’m talking about how a libertarian would interpret the question due to its ambiguous phrasing. My only point is that of the original parent comment: the methodology of the researcher is bad.