I think the questions on the test linked by Jeff look reasonable for 5th grade arithmetic, and fit my recollection of 5th grade math ~25 years ago. While I think that the multiple choice answers can provide useful insight to a student’s teacher, I’m not entirely certain that “plausibility” is useful as a metric for overall aptitude. I would strongly disagree with its use for obtaining academic accreditation.
Ancel, I think “Plausibility” was a poor choice of words. I would guess that it was chosen to infer that there was the ‘appearance of reason’.