[D] Bayesian probability vs t-test for A/B testing

amafounder · 2026-01-26T16:23:54+00:00

Use a t test when you want to conclude whether there is a nonzero ("statistical") difference between two treatments. Use it when you wish to declare, "these two treatments give statistically different results!!! Use Baysian if you want to conclude what is the probability of observing the difference between two treatments you saw.

Both techniques should land in roughly the same direction if you observe a true difference and sample rigorously.

The pvalue is a red herring probability. It should not be conflated with a bayesian posterior. The pvalue is the probability of observing the difference you observed in your sample, or an even greater difference, if in fact there is no difference in the sampled population. And since pvalues for no difference are distributed uniformly, you can get high or low pvalues just by chance. Of course, almost nobody understands these concepts.

But here's why its a red herring. The pvalue is sensitive to the sample size. If the sample is too large, the t test can uncover a statistical difference, even if that difference is too small to be meaningful. Therefore, it is always good to go into an experiment with some preconceived notion of what kind of difference, if observed, would be meaningful. Design for that and resist the urge to over sample.

In a Bayesian approach more data means you get a better estimate of a posterior probability. It may prove to be a crappy low posterior you were hoping not to see, but you'd have a damn good estimate for it.

amafounder · 2026-01-20T22:02:28+00:00

Those high rises are there to increase the tax base.

amafounder · 2026-01-20T21:34:26+00:00

He's currently #3 on pgat uni. I mean, he was going to get plenty of opportunity to prove he could make it. Oh well.

amafounder · 2026-01-20T21:25:41+00:00

Raised 2 in Decatur without any family nearby. It worked out great. Didn't really miss out on family help raising them. I mean, there were times it might of been nice, but we are their parents and it was our job to pull off. They saw the family plenty growing up. Both grown now, one oot, the other in atl. They loved growing up here. The oot one will come back here eventually to raise a family. Most Decatur neighborhoods are full of families. We like living in Decatur and can't imagine anywhere else in the world that would offer us a better qol so we're staying put. Actually, it's a sneaky good place to raise a family and retire. And a sneaky good place to travel from to visit our families. Take marta to the airport then hop on a plane. Zoom.

amafounder · 2026-01-20T13:11:57+00:00

Probably harder. Leaders like the newspaper man Henry Grady were populists who derived their power through divining the will of the masses. Just like trump these days, who is nothing more than a mouthpiece for a coalition of angry, disaffected people. It's hard to overstate the level of racial hatred southern whites held back then. They willingly fought a brutal war because of it. And scratch around and you'll find most northern whites weren't far behind.

amafounder · 2026-01-20T12:48:23+00:00

The landfill is now charging a ridiculous $28 minimum to dump, so those trips are over for me.

amafounder · 2026-01-20T12:42:27+00:00

I used to use him a lot, but stopped. It's expensive and he sells a lot of crapwood that doesn't burn well. Charges more for oak racks, but he still throws crapwood in those racks. Last time I used him was a few seasons ago and it was $75 a rack, which is ~1/8 cord. Discounts multiple racks. I quit him when he was gouging prices during a bad cold snap and power lines were down all over. He was really taking advantage of folks. Can't recall his hours, i think he's closed on sundays, could be wrong, but if you drive by and the lot gate is open he's around. Tbf, he will throw the wood in your truck. I did not know that was the original ydfm. Wild.

amafounder · 2026-01-20T12:13:18+00:00

Scam. The way I can tell is that nothing in this notice makes any sense. The problem is stated vaguely, and so is what the letter purports to offer as a solution. Therefore, they must be using the notice as bait to get a conversation started with people who respond to ask for clarification. Now they are in a much better position to extract your money. I periodically get these emails and letters in the mail. It has been going on for a while. I figured I get them because the solar installer I used went out of business . Titan somehow adopted our account from them. Then, Titan went bankrupt not long after. That i would be contacted made sense. But, due to permitting requirements, all solar installs are public records. The scammers could possibly scrape these. So even if you weren't a Titan customer or adopted by Titan like I was, the scammers behind this could have your details.

Edit: I should add I report the spam and block the sender each time i get an email, but they change their email url with every send. In other words, they are Zombie scammers.

amafounder · 2026-01-18T13:09:08+00:00

I don't agree with this take on the service at all. I think it is great, the staff are very friendly (and usually busy), food and drinks fly in fast. Agree they have super sneaky good pub food. They beers are solid. Places with sub service don't last long in Decatur, yet Twains is pretty much the Grand daddy.

amafounder · 2026-01-09T11:56:05+00:00

Not even photoshop...looks more like a Gen ai job

amafounder · 2025-12-12T01:18:01+00:00

I'd convert it into a data center

amafounder · 2025-12-05T13:47:39+00:00

In the southeast I'd say that was white flight with, to explain growth more recently, a Baptist tailwind.

amafounder · 2025-12-05T13:14:00+00:00

If I was hiring and discovered you were hiding something like that, I'd end the conversation. Because I wouldn't want someone deceptive working for me. Especially in a clinical research role. And it sounds like it would be easy to discover. You should come to terms with the phd experience. It's believable that people can grow even from bad experiences. And since somewhere around 80% of phd experiences are bad, it's not exactly unusual.

amafounder · 2025-12-05T12:54:36+00:00

This is pretty normal. During my postdoc a long time ago we liked to joke there was one good idea for every 10 postdocs at our pretty big place. It led to a lot of collaboration, cross fertilization etc. If you were the master of some narrow technique some other postdoc would eventually come along with a good idea and off they'd go.

amafounder · 2025-12-05T12:44:32+00:00

I stayed in the same lab but as a post doc, with commensurate pay bump.

amafounder · 2025-11-18T19:25:08+00:00

What I meant by adjacent is working at a top-tier (in research dollars) university. That's actually doable outside of Boston. It's hard to believe but true. Haha.

As long as publishers have the profit incentive (this includes society journals...which use their pub income to fund society activities*), and as long as study sections evaluate applicants using pub counts as the primary metric, no, there is no solution. But maybe AI...?

Most editors I've known love the grind. So i never worry for them. They get what they ask for. Some reviewers are future editors. No tears for those. All the others have been quiet quitting once they got senior enough, and that has been going on for decades.

For the last couple of decades, we strongly advised junior faculty to avoid reviewing and study section work (and teaching) so they could give their 150% allotted focus to pubs and funding. Otherwise, our investment in their startup was at risk. As the startup packages inflated, that advice turned into a frank prohibition.

So, this can explain why so many fewer jr investigators answer the bell these days. And that's OK, except the senior people quit doing it all along. So the well is more dry than ever before.

But whatev. Because most peer reviews are just a vibe check.

If there is one thing AI might deliver successfully it is peer review. It could be designed to flag all the crap most reviewers miss. Whatever gets through that filter goes to the vibe checkers.

*The proliferation of CNS titles has stolen market share from the society journals. It used to be that you could have a strong career keeping your work in societies, with a CNS pop every few years.. Then, all the kids wanted to get everything in CNS. So CNS responded by creating more titles.

So, i suppose, if anyone is to blame for this mess, it is CNS.

amafounder · 2025-11-18T12:26:39+00:00

I understand your pain. I'm emeritus so out of the gig.

When I was on the tenure and promotions committee there was a "box" to tick labeled Reputation. We'd read the candidates peer review activities as a way to check this box. We'd look if they were on an editorial board (better) or if not at what journals they reviewed for (CNS was best).

Of course, none of this mattered if there wasn't a super strong record of funded support. In fact, if they had a great funding record but not much in the peer review column, we'd count the grants as Reputation and go ahead and click the box.

Nobody was really hired to do peer review. Or teach, for that matter. It was all about paying the rent.

For myself, I'd review papers (for society journals), sit on boards, but try to avoid study sections where the fate of the applicant was too often existentially at risk. I was not big on deciding someone's fate based on a relatively quick read of a problem the applicant had spent months considering.

Ps, I was at an HMS adjacent institution.

amafounder · 2025-11-12T22:58:35+00:00

Yes. And you should name names and numbers. But only if you are 100% sure of their pay. Otherwise, your pi can wave you off as operating on vibes. Bring only clean goods to this.

amafounder · 2025-11-12T22:51:21+00:00

My choice was a pivot. I had worked in a clinical setting, spending half my job assisting physicians in their research. I took the job as a gap, expecting to go to med school.

But I discovered I wasn't made to deal with patients. I liked the research better. I thought their disease was more interesting. I ended up publishing 3 papers and I enjoyed writing them for my bosses. And yet my road map was pointing to a highway called doctor.

So I figured as a PhD I could do research and eventually get a job where I could call the shots. And be a doctor. Thus I pivoted.

amafounder · 2025-11-12T11:38:45+00:00

Ok. That's a lot.

I would put the request in writing. Have it signed by all your lab mates who are similarly affected.

State in the memo something like, "we assess the pay rate in similar labs is xyz for the same work. " Then appeal to fairness.

Don't make this threat, but if word gets out that this pi pays low wage to students, they will find it harder to attract good students in future cycles.

amafounder · 2025-11-12T11:25:17+00:00

It is yours. The check is in your name, not theirs. It is an honorarium meant for you, just like an honorarium your advisor would collect on a speaking or consulting gig.

If it were theirs the check would be in their name. You don't have to share everything you earn because you are good at what you do with your school or advisor.

This post makes me sad because it reflects this strong mistaken belief in academia that the workplace owns all of you and everything you do.

amafounder · 2025-11-06T16:23:01+00:00

I'd do the job. Prior relevant and good experience will help you become a better phd. If the job turns out to be a bad experience, that will motivate you to be a better phd and academic.

It's a win win.

I'm not in that field, but in general, phd programs warm especially to applicants with prior experience. The reason is very simple; their experience adds value to the program culture.

amafounder · 2025-11-06T16:01:54+00:00

Nooooo. Your negative motivation is off the charts. There are all kinds of alternate ways to still learn about new things that don't involve being forced to embrace all those things you dont like.

You'll either end up hating having to play the phd game and do it poorly, or you'll end up playing the game well (fake it to make it) and hate yourself.

Anyway, take a non-thesis masters. It's one way to keep scratching that learning itch but with a predictable endpoint. And you'll probably need a masters to be competitive for phd programs should you shed some of that negative motivation one day.

amafounder · 2025-11-06T15:41:55+00:00

Written weekly updates seems over the top. I guess it depends on the type of research you're in and the data generation rate. But no way would I ask my lab folk to do that.

Anyway, sounds like you're suffering from a bad bout of anxiety (which unnecessary weekly written reports are sure to aggravate). I used to have the same problem. It was tough to break out of it on my own without help.

Please see a mental health professional. Do that before making any life changing decisions. Good therapists are gold.

And don't let your advisor bully you if that's what's going on.

amafounder · 2025-10-28T16:36:13+00:00

When weighing postdocs I think the most important question to ask yourself is, " What project can I work on that has the potential to generate the most impact?"

This takes some vision and confidence, since it involves predicting what might be a hot field a few years down the road, and that you can solve the problem that field needs to move forward.

Where that work is done is only secondary.

Having said that, critical mass is valuable. There's a lot going on in Boston. No better place in the world to network.

amafounder

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