The funny thing is, I imagine I'd fail this, and a lot of other "interview" questions. (Not fizzbuzz incidentally :P)

Why? Because my brain just doesn't seem to work in the way people expect "experts" brains to work in our world of tests/qualifications.

Now for context, I don't consider my self some wishy washy "Oh I have a different KIND of intelligence" making-excuses dumb as nails nancy. I've worked several years now for my nation's statistics agency. I've written programs to calculate things professional statisticians couldn't (indeed that seems to be one of the reasons I get to keep my job :P) and just about every useless bloody stat there is, I've written my own probabilistic data linking software, finished in the top 10% of unrelated competitions on kaggle, and my formal qualifications are in economics. I don't think I'm the greatest thing ever, but if i might be so blunt, I feel I'm at the stage where I can confidently claim to have "proven my capabilities".

But I haven't memorized Bayes theorem (or any other probability or math-formulas), despite having applied it about 100 gazillion times. And despite being an economist, I haven't memorized "the relationship between bond prices and interest rates". Now, I could try to reason these things out from scratch in front of you, but I imagine most people in our world would see that as a "weakness" or trying to hide the fact that I couldn't answer the question.

With the probability one, I'd start going down the various interpretations of probability and whether your notion of probability is internally consistent/justified, etc etc etc. I doubt I could write the math on the white board of the top of my head in an interview (and i know several statisticians who couldn't also), but I could probably outperform most of the candidates who could in its application in the real world (speaking from experience), or be able to question whether there is a better tool for the job in the real world.

With the bond one, I know there's an answer that you expect me to give from rote during my education. But i won't. I haven't memorized it (because from experience, memorising these types of things is bad form, conditions you into erroneous thinking when they eventually turn out not to be universally true, and is far worse than reasoning, questioning or thinking about problems). So i'll ask you to describe your idea of a bond to me. I'll ask you to describe your idea of interest rates. Why are the interest rates rising? Maybe then, depending on what answers YOU give, I'll say "well then obviously bond prices must move inversely to interest rate movements", but there's just as much chance i'll pick up on some mistake you've made and never reach that point.

Now I'm not attacking you specifically. I don't know you, or what we think of each other, or how we'd interview each other. But from my experience, most people/recruiters/employers/interviewers would take my behaviour as a negative sign. A sign of "stalling" or "evading the question". Questioning, or reasoning, or skeptically interrogating things or mulling over questions for long periods of time, especially if they consider the answer "known", is a "bad sign".

And the rote learner, who'd just happened to memorise a particular formula or spent most of their time in one particular context, or bought the book on interview questions for said industry will get a big fat tick.

Moral of the story: Please don't use "interview questions" :P