Normal distribution, degrees of freedom, etc etc my brain is blue screening. How am I supposed to remember all this shit? HELP.
I'm bombarded with like 12 new complex terms in each lecture that I'm supposed to just fully understand. Gdhsjfbe fuck my ADHD brain.
Look all you need to know is Bayesian inference, everything else is window dressing
updating. P(not full of shit) = p(full of shit) - epsilon / some shit
Yep still full o shit
Please tell me this is a shitpost because this is the stuff Yuddites use to justify their weird shit
I don't even know how to explain it (Link is catalogue of people talking about and "sneering" at (hence the name) the weird shit Yudd and his cultists get up to)
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OH MY GOD THEY HAVE MULTIPLE SYMBOLS THAT MEAN THE SAME THING, WHY WOULD YOU DO THAT IN MATHS?
Higher math is actually notorious for this. The notation someone uses is a product of when they went to school, where they learned stuff, and what the background of their teacher was. There's absolutely no standardization, despite what you'd naturally think. It's a mess.
The notation thing or math in general?
Either way, I think most mathematicians would agree.
Referencing this:
Show
Edit: In all seriousness, though mathematicians should copy chemists and develop some kind of standardized notation.
i vs j for the imaginary part always annoys me. if you're an electrical engineer, you're wrong - I'm sorry.
OH MY GOD THEY HAVE MULTIPLE SYMBOLS THAT MEAN THE SAME THING, WHY WOULD YOU DO THAT IN MATHS?
this is an anglo problem, it infects everything they touch
Everything should be standardized in academics, it makes no sense to needlessly bloat things
Don't worry, nobody understands what the fuck is a degree of freedom.
Or statistics in general
That's great but I have an exam in 5 weeks that I have to pass
Well in terms of figuring out what to study why don't you take a population sample x ~ X where X is past tests, then work out for a given pass mark which questions you need to be able to answer such that the expectation value of a given test is higher than that?
Or something idk
Do you have a student center tutoring program you could use for help? It sounds like your prof is just throwing info at you without really explaining how to understand that information. Having someone more able to go over it with you directly, correct mistakes, etc. should be helpful.
Sounds like we don't have a ton of people who can help with stats, but as an educator I definitely want to help you learn your best!
I get it, always hated statistics. Never quite figured how to reason about samples vs populations. Your best bet is to use all of it in practice. Try to understand why each term has that name. You're not trying to be a stastician so you just need to pass.
hit them with the "wow, normal distribution..." they will get it and you will be so popular
Call it a Gaussian distribution to sound fancy.
Stats can move pretty fast that's true. I think the way up stay on top of it is to read before the lecture, use the lecture to take notes and understand what the teacher wants you to focus on, and to do the homeworks (possibly extra homework) to use repetition to force it into your brain.
So basically... more work at the stuff you already knew to do lol. Shit sucks.
On the plus side this stuff is kinda useful to know in that you'll be able to more critically read stats in the lying liberal media.
For basic stats you can ignore a bunch of the underlying theory and just memorize a couple of formulas (or how to apply those formulas if you get a notes sheet on the test) and get good at finding numbers in tables.
The normal distribution represents the idea that most sets of data tend to cluster around the mean (if you grab someone at random, you are more likely to find someone who's 5'8" than 6'7").
Degrees of freedom is the number of observations in your sample minus 1 and is used to look up a value in a table.
Thank you! Good advice! I know X^2 tests of goodness of fit and independence are (Ei-Oi)^2/Ei, but I'm having trouble understanding what i means, I've been told it means category, but the context is hard for me to grasp (which category? When? What counts as a category?)
(I've grasped what degress of freedom and normal distribution are, I was just using them as an example lol but thank you, your explanations made it clearer for me)
No prob!
The i denotes a category that's determined by the researcher. You can think of Chi squared tests as testing the deviation from an assumption (typically that whatever you're looking at is randomly distributed). So it can be something as simple as heads or tails in a bunch of coin flips - you could calculate your _E_xpected rate of heads - _O_bserved rate of heads / the _E_xpected rate of heads
Here's a really detailed explanation. In evolutionary bio you can use it to see if traits are undergoing selection. Suppose in tribbles allele P causes black fur, p causes white fur, and the heterozygous condition is gray. You know from previous sampling that the rate of appearance for P is 0.80 and p is 0.20. You could then estimate that you would expect to see 64% black Tribbles, 32% gray Tribbles, and 4% white Tribbles. If you go out and your sample only has, say 20% gray tribbles, the chi square can tell you (O_gray - E_gray, etc) if it's reasonable to think that was random sampling error or there's something else going on (possibly sexual selection or predation).
That helps a lot, thank you! Exellent use of Tribbles
Glad you found it useful! Feel free to ping me if there's anything else I can help with.
Degrees of freedom is the number of observations in your sample minus 1 and is used to look up a value in a table.
doesn't this lead to a lot of extraneous variables that are actually linearly dependent on a smaller set? or worse -- overconstraining?
This isn't a universal definition of degrees of freedom, it's just "degrees of freedom as it applies in an undergraduate level stats course," which is typically for the t distribution. It's n-1 because you assume all your observations are independent of one another. In other contexts (ANOVA, e.g.), the calculation is different.
I get that, just thought it was a strange definition given what degrees of freedom actually refers to
if its any comfort at all, I passed my intro to statistics subject in first year uni with no mathematical experience past year 8
I know it's stressful, but I'm sure you've got a better understanding than you'll give yourself credit for. Goodluck!
It might help to understand degrees of freedom in a more general context. In a physical system, the number of degrees of freedom is the number of things that have to be specified for me to know the complete state of the system--for me to know "everything there is to know" about it.
Imagine I've got a featureless point particle floating in a box. How many numbers do I need to write down to specify everything there is to know about the system? Well to begin with, I need to know where the particle is in the box, so I need three numbers: one for the x dimension, one for y, and one for z. That's three degrees of freedom.
Does that tell me everything there is to know? If the system is an unchanging snapshot sure, but not in a real dynamical system. If the particle can move, we need three more numbers: one for its velocity in x, velocity in y, and velocity in z. If you have those three numbers, you can predict where the particle will be at any given time, assuming you know where it started.
So, we'd say this particular system has six degrees of freedom: position in x, y, and z, and velocity in x, y, and z. There are six parameters that can vary to make a unique state of the system, given the constraints we've put on it.
I had a Stats professor from China and she was somewhat hard to understand, and we spent a week learning to calculate "Elo" and I had no idea what it was, just had to wrap my head around these equations without knowing what it even represented.
The next week she was showing a variable that could go down to zero, in which case that variable "didn't matt" and we could simplify the equation.
She kept saying "didn't matt"
I realized that she had trouble saying "er" because that's a famously weird and difficult sound to make, and only shows up in English and a couple other languages... So she didn't even try at all, she just skipped over that sound whenever it came up.
Then it hit me. Elo. We had been learning to calculate FUCKING ERROR
I feel understood, I’m unironically going to have a breakdown the next time I’m taught some shit named like “Gretchen’s integrated crosscube” that I have to file into the thousands of of other microconcepts that will all be on my final
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