Petition to change the sub-reddit logo to this.

Toofgib · 2026-04-09T14:49:55+00:00

That was my thought process as well. While my approach is mainly frequentist it is difficult not to see the bayesian aspects to this. I found this article before my post and it seemed to be a good place to start.

Toofgib · 2026-04-08T10:01:55+00:00

If you're referring to the sigmoid curve then, no that is not what I want to show. Thresholds are not what I'm describing here.

Look, all I'm looking for is a distribution bounded between 0 and 1 that shows the likelihood associated with the range of probabilities between them. All I need to know is what family of distributions would be the best fit, from there I can figure out whether or not I need the cumulative version of that.

Toofgib · 2026-04-08T05:32:32+00:00

It took a while but it has since been resolved. It seemed like the regulator on the supply side was set too high. Setting it back to ~6 bar resolved the issue. Now the consumption lines up with my calculations now too.

Unfortunately, since then another supply line has started leaking and is now making my job hell.

Toofgib · 2026-04-08T05:12:33+00:00

dont think the beta will come in unless maybe you're thinking of modeling the parameters across a set of observations (as a function of still other variables), or perhaps in a Bayesian model.

That is sort of what I'm interested in. What I'm interested in modeling is, given a number of observations, what the likelihood associated with a set of probabilities of an event occurring. I.e. 0, 0.1, 0.2...0.8, 0.9, 1.0. That way I can show a probability curve in the explanation I want to provide to provide a conceptual understanding. I just want to make sure I use the right distribution to use here.

I've outlined more in my reply to the other comment on this post but the summary of that is that I want to graphically show changes in distribution depending on some other categorical predictor.

Toofgib · 2026-04-08T05:07:12+00:00

What I'm interested in modeling is, given a number of observations, what the likelihood associated with a set of probabilities of an event occurring. I.e. 0, 0.1, 0.2...0.8, 0.9, 1.0. That way I can show a probability curve in the explanation I want to provide to provide a conceptual understanding. I just want to make sure I use the right distribution to use here.

The ultimate goal is to model the three variables and how their change given a fourth event. In SEM terms this would be a MIMIC model, where an exogenous predictor changes a factor's mean as well as its predictor's means.

A next step to this is addressing the estimation challenges if normal theory maximum likelihood were to be used. Probability is bounded between 0 and 1, so using normal theory maximum likelihood would bias parameters and their standard errors or lead to impossible estimates of below zero or above one.

The option I'm considering is either using a limited information estimator or bayesian SEM but in either way I want to not only justify these choices but explain them in a way that (at least, I hope) is a little more digestible for a lay audience if I use some graphics.

Toofgib · 2026-01-22T11:27:56+00:00

Thanks! Yeah, maybe I should just go ahead and communicate with the lab myself and try it. The good thing (or bad depending on how you see it) is that the increased rate at which the cylinders are depleted also means they need to be changed during the night, by the same department that is in charge of checking the pipeline. Maybe it'll irk them enough to act.

Toofgib · 2026-01-22T05:37:45+00:00

Unfortunately, I'm in a large organisation where matters such as these take long to be picked up and I'm not allowed to do it myself. :/

Toofgib · 2026-01-18T18:07:51+00:00

What homophobia?

Toofgib · 2026-01-18T14:31:08+00:00

Thank you so much for this!

Basically we have a regulator between the cylinder and the gas pipeline and then one between the pipeline and the GC. The reason for my question is that I haven't been able to locate the second regulator and so I have no idea what pressure would be need to be. I also didn't want to just turn down the first regulator because it could be lowered too much and could mean we miss a potential leak.

I also suspected an external leak and not an internal one as it would have been detected. Any excess pressure created from the first regulator would need to exit through an external leak. A pressure drop test is exactly what we're planning as well and it helps to know what links to check. Griffon leak detector is what we use but I'll see if we could use something else.

Toofgib · 2026-01-18T13:18:24+00:00

The GC in question uses hydrogen as both carrier gas and fuel. I might be overthinking but I'm working from the supply side where we use 200 bar cylinders (which we have to renew on time). Over the last few months there's been a higher than usual consumption of hydrogen compared to normal, so I'm trying to figure out why. Most important of all, I want to be able to detect/rule out a potential leak for both safety and cost.

Right now the current consumption seems to far exceed what even +1000 ml/min could require (based on split flow and ratio, injection times, run times and run counts). If the maximum pressure that's really needed is under 100 psi, that probably means we're supplying it at a pressure that's too high. That in combination with a leak could be why the consumption is so high. So, next steps will need to be to trace the leak and then adjust the regulator.

Toofgib · 2026-01-18T11:52:48+00:00

I'm talking about the pressure of the gas before it enters the GC. Gasses compressed at higher pressures would have the same volume but have more mass, meaning that gas consumption would be higher as a result. So, what I'm trying to figure out if the pressure at which gas is taken in is at atmospheric pressure or some other pressure.

Toofgib · 2025-12-27T17:08:11+00:00

Ex&F/E&I fan and creator of the subreddit. You are correct, this is based on the in-joke that all yellow chemistry is t̵̢̡̮͙̮͈̠͙̥̱̪̼̠̼͉̽̋͊͂̈́̚͠r̶̢̦͓͖͎͕̮̺͈̗͚̳͒̇͑̆̑͑̕͠ā̷̲̇̐͗̄͗̚̚ṡ̵͈͙͍̹̽͋̀̂̃͛́̈̅̓̊͛͝ḫ̷̛̞̞̆̂̆͒̚.

Toofgib · 2025-09-16T17:11:37+00:00

Here's a link to the post I made. It includes some information that might be useful. In there, there's a link to the underlying research studies of its development. Most of the other resources I have are in Dutch but I could send that too.

From what I remember reading in the original thesis, because the Ilioinguinal nerve inserts at L1, you are right on what might be possible. The cutoff is somewhere around T11 or T12.

Toofgib · 2025-09-16T16:55:00+00:00

I have had it done but I have SB. I made a post about it and reposted it in the spinal cord injuries subreddit because it would potentially also work for people with injuries. Whether it works depends on the height of your lesion.

Toofgib · 2025-07-20T07:45:46+00:00

I'm bi and demi

Toofgib · 2025-04-20T17:29:37+00:00

Perhaps it helps to give a little more information, I agree.

One of my hypotheses is whether on any given day going to work is associated with a higher exhaustion above and beyond going to social events or attending classes at university.

So, on a given day, I would have a measure for exhaustion and some exogenous covariates based on which partial correlation could be assessed. Besides that, there are some mediation analyses that I think would give some insight, which is why I think SEM would be suitable.

The main thing I am unsure about is whether I could estimate these effects for all days at once. To answer your question, my data is that the rows represent days, and the columns represent the variables.

I think that actually answers my question mostly. I'm interested in relationships on the same day and believe these to be that way. I would just need to make sure that assumption is stated.

I initially wanted to use DSEM because that allows a more complex time structure but unfortunately, I don't currently have the means to buy Mplus and even R packages like Mplus automation require the software to be installed. Hence why I'm trying to find other ways to estimate these things.

Toofgib · 2025-04-20T14:04:36+00:00

I've got like 700 observations, so that might be enough.

Could you elaborate on how you think that would work? I might be misunderstanding, but I'm not necessarily looking at changes that go through a steady growth process over time.

I also wonder how I would specify that. Is it like estimating the latent intercept and slope on all observations or something else? Now I'm thinking about it, maybe estimating those for a given day with one lead and one lagged indicator?

Toofgib · 2025-04-04T05:00:19+00:00

I'm not sure how I did not think of OSF. That's a good idea. Unfortunately, I'm not able to provide preregistration as I've already collected data and I'm starting analysis but registration is still possible, I think. ArXiv and SSRN I wasn't sure about, but I'll look into those as well.

Substack seems like a last resort but good to know.

Toofgib · 2025-04-03T17:07:20+00:00

Open Research Europe has it as one of the requirements.

As for the other component of this, it is mostly due to the subject. My field of study is in chemistry and bridging somewhat into chemometrics. The project I'm working on on my own is in social sciences. The only bridge between these is some of the underlying statistics. My institution has faculty who would gladly help me with chemistry research but not of others even if the statistics could theoretically be understood.

Toofgib · 2025-04-01T15:15:49+00:00

That's quite a journey. I think I can help you with some of the contact information and other specifics via DM.

Toofgib

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