Sending out the r/statistics about Nevin Manimala bat signal! Soliciting advice on selecting statistical methods.

Good morning, statisticians of Reddit!

Long time lurker, first time poster!

I want to preemptively apologize for the less than adequate manner I am about to attempt to explain my question. This is will inevitably be like going mechanic and making strange noises with my mouth to tell him what is wrong with my car.

Thanks in advance for any insight!

My dataset contains longitudinal cohort data spanning 12 years for a high school.

Students per graduating class = ~450.

The association I am trying to explore is whether or not students enrolled in the STEM program (yes or no; 1 or 0) have a higher graduation rate (% of students that graduate on time with their cohort in 4-years) than students not enrolled.

I would like to first do some form of clustering, stratifying, or whatever is appropriate to distill the student population down into two homogenous groups – with the only difference between the groups being the dichotomous independent variable.

GROUP A (IV = YES) = Graduation Rate %

GROUP B (IV = NO) = Graduation Rate %

Both groups have been clustered, stratified to have the same general makeup. The only difference is whether or not they are enrolled in a STEM program.

My hypothesis is that, controlling for factors like race, gender, income, etc. (by clustering or stratifying) students enrolled in the STEM program have higher graduation rates than those not enrolled. This is as far as I want to go at this point. If something happens to show up and it appears to be a statistically significant (?) result, I will dig deeper into the WHY.

My questions are:

  1. How can I make these groups and what method is most appropriate?
  2. What statistical test would I use to determine if being enrolled in a STEM program is associated with graduation rates (a 4- year percentage ranging from 0-100%)

Thanks again for any help or direction!

submitted by Nevin Manimala Nevin Manimala /u/LurkAndWork
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What’s the best deal you’ve gotten on a car?

I think I just achieved a personal record yesterday, having found a freshly posted 98 Camry for sale for $600. The only details were the price and mileage (172k). When I met the seller, it turned out to be one-owner, religious maintenance records for the last 100k, locally bought In SoCal, V6, and new tires/battery/alt/starter. It’s even quieter at 80mph than my two-year-old $30k Mazda. It’s just perfect as a nice transportation appliance.

So, that’s mine – what’s your crowning moment of automotive purchasing?

submitted by Nevin Manimala Nevin Manimala /u/NuttyMudMaker
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Why you can’t untie a knot by tying another one.

I’ll sketch two short proofs. The first one using topological methods, and the second one using smooth methods.

1) The Eilenberg swindle:

Imagine that I have knots A and B so that the connect sum A#B is equivalent to the unknot O. We want to prove that both A and B are unknots. We will do this by starting with an unknot, and perturbing it to get A. This will also prove that B is an unknot because then O = A#B = O#B = B.

Starting with our unknot, we can perturb it to get A#B, so we can also perturb it to get A#B#A#B and A#B#A#B#A#B, etc… we will keep doing this until we get K=A#B#A#B#A#B…, with infinitely many knots each one getting progressively smaller, approaching a limit point. Now, we can also think of K as A#(B#A)#(B#A)… so we can cancel the Bs with the As in parentheses to just get A.

2) The disk method:

We start with an unknot A#B. Again, we want to prove A and B are unknots.

We know A#B must be the boundary of a disk D because it is an unknot. Furthermore, we can create a sphere S around A which separates it from B. Generically, D∩S consists of several circles and a single arc which goes between the two points where S intersects the knot. This arc must go between two boundary points of the disk, separating it into two smaller disks, one of which bounds A, and one of which bounds B. Thus, both A and B are unknots.

submitted by Nevin Manimala Nevin Manimala /u/leguminophobia
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[Opinion] Best math genius ever lived: Evariste Galois

Galois Theory is majority of his genius, He has lots of contributions to math in mostly Algerba but many field are involved. And all this at the age of 18 and 19.

Unfortune death of Evariste in 20 years old. He could change the mathematics as we see it.

submitted by Nevin Manimala Nevin Manimala /u/sokuk
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Cars that look worse with more or less doors?

Example: Toyota Landcruiser, The 2 door makes me cringe everytime I see it, it looks deformed.

2 door https://static.pakwheels.com/2017/10/Toyota-Land-Cruiser-Prado-3-Door.jpg

4 door https://carsfeatured.com/wp-content/uploads/2015/11/2017-Toyota-Land-Cruiser-07.jpg

Any other examples?

submitted by Nevin Manimala Nevin Manimala /u/iamthiswhatis12
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Question concerning graphs

I have a couple of directed graphs that illustrates the same phenomenon/network , but under different conditions. Each node has always only one outgoing edge and every graph has the same nodes., but sometimes with different edges. Because I’m not really familliar with graph theory, I got stuck at the following : I want to relate/compare these graphs to discover how to conditions influence them. Are there any quantitative properties or characteristics of graphs, that I can use? Until now I just I used properties like number of cycles, where cycles occur etc., but it’s not sufficient. Do you have any ideas to research the structure of these graphs?

submitted by Nevin Manimala Nevin Manimala /u/PhPanda
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Which countries should I prefer in Europe for pure maths PhD?

I have a question,

Which countries should I prefer in Europe for pure maths PhD?

This is the biggest maths community I know and must have people from almost all demographic regions. Which countries in Europe value maths PhD. PhD degrees of which countries are universally recognised?

From what I have heard through people and different sources. I have the made the following list.

  1. GERMANY.
  2. SWITZERLAND.
    3.FRANCE.
    4.BELGIUM.

What are some other countries I should add in this list?

P.S.I am from India.

submitted by Nevin Manimala Nevin Manimala /u/mathaman
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