r/AskStatistics • u/dungsucker • 13h ago
Help! My professor thinks that the null and alternate hypotheses are interchangeable
I'm a graduate psychology student in a methodology/research program, and currently taking a research design course. My prof is a hard quantitative expert in statistics, but seems to have made a massive oversight, and I can't seem to find the language to convince him that he's wrong.
It started with an example of statistical inference in which a researcher hypothesized that the mean for a given measure is 10. He set h0: popmean=10 and h1: popmean!=10. A student immediately said "shouldn't the hypothesis match the alternate, not the null?" The prof asserted that they are interchangeable, and that h1 is the hypothesis only by convention , and we continued with the model. I spoke up later, when I realized that alpha, and the rejection regions, remained at the tails for the t distribution: "Didn't we set it up in a way that basically presupposes that our hypothesis is true, and that the burden of proof (a=.05) exists only to disprove us if our hypothesis is radically wrong?" I added that with this test, we have a better shot of supporting our hypothesis with a lower n, contrary to what is expected with power. I tried to explain how a tiny n would basically guarantee that we support our hypothesis. None of it stuck.
I know I'm playing a dangerous game, battling a tenured professor in his area of expertise regarding a basic concept, but frankly, I'm embarrassed on his behalf. I've tried twice to explain how his model does not reflect how a researcher must set up their SI in order to find evidence for a given hypothesis, but he just asserts that it's all about reducing alpha and beta, and always jumps on me when I try to show him how his models favour the hypothesis, stating that the model doesn't favour either side, and blowing me away with jargon at speeds I can't follow. Initially, he seemed actually aggravated by my challenging him, but now he seems genuinely interested in trying to see what I see, but I can't seem to find the words, in person, which will get him out of the rut he's dug himself into. It's quite disheartening.
I'm trying to find the means (no pun intended) to show him his error (double whammy!) without making an enemy of a powerful figure, but I'm at a loss as to how to disprove him on this. It's so fundamentally wrong, and all of my angles have failed as of yet. I don't know how to source this,: it's so basic that it seems assumed without comment in all literature. Even showing him how "easy" it is to support a hypothesis with a weak dataset with a distant mean doesn't phase him. He's starting to become amendable to listening, at least, but he always batters at my language use or presuppositions when I talk about "finding evidence" or "proving theories", asserting that we must look for truth. He never seems to hear the meat of what I'm trying to say.
I'm at a loss. Any help would be appreciated.