Mike X Cohen PhD, Sincxpress Education
@mikexcohen.bsky.social
Check out my longer posts on Substack (mostly detailed tutorials about data science and LLMs). mikexcohen.substack.com
Explore my video-based courses and books ➔ sincxpress.com
Explore my video-based courses and books ➔ sincxpress.com
How to live a happy life, according to the most elegant equation in humanity. (Hint: it's the math version of "omit needless words.")
mikexcohen.substack.com/p/eulers-ide...
mikexcohen.substack.com/p/eulers-ide...
November 19, 2025 at 9:19 PM
How to live a happy life, according to the most elegant equation in humanity. (Hint: it's the math version of "omit needless words.")
mikexcohen.substack.com/p/eulers-ide...
mikexcohen.substack.com/p/eulers-ide...
In my latest substack post, I show how to measure gender bias in open-source LLMs. The post comes with detailed explanations and a Python notebook file that you can easily adapt to any other biases.
Curious? Come check it out :)
mikexcohen.substack.com/p/gender-bia...
Curious? Come check it out :)
mikexcohen.substack.com/p/gender-bia...
November 6, 2025 at 3:08 PM
In my latest substack post, I show how to measure gender bias in open-source LLMs. The post comes with detailed explanations and a Python notebook file that you can easily adapt to any other biases.
Curious? Come check it out :)
mikexcohen.substack.com/p/gender-bia...
Curious? Come check it out :)
mikexcohen.substack.com/p/gender-bia...
No comment.
October 27, 2025 at 12:36 PM
No comment.
Statistician: Someone who has their head in an oven, their feet in an ice bucket, and says "on average I feel fine."
October 22, 2025 at 6:30 PM
Statistician: Someone who has their head in an oven, their feet in an ice bucket, and says "on average I feel fine."
If I had a million euros (that's 1.170686 million USD), I would do Daily Data Challenges to master machine-learning. Like this one, which involves running a t-test in Python to compare two random samples.
Act like a millionaire. Solve Daily Data Challenges.
mikexcohen.substack.com/p/ddc-15-two...
Act like a millionaire. Solve Daily Data Challenges.
mikexcohen.substack.com/p/ddc-15-two...
DDC-15: Two-samples t-test
A data challenge a day helps you master machine learning
mikexcohen.substack.com
October 17, 2025 at 12:54 AM
If I had a million euros (that's 1.170686 million USD), I would do Daily Data Challenges to master machine-learning. Like this one, which involves running a t-test in Python to compare two random samples.
Act like a millionaire. Solve Daily Data Challenges.
mikexcohen.substack.com/p/ddc-15-two...
Act like a millionaire. Solve Daily Data Challenges.
mikexcohen.substack.com/p/ddc-15-two...
“King – man + woman = queen” sounds smart until you actually check the math.
Spoiler: it’s fake news.
mikexcohen.substack.com/p/king-man-woman-queen-is-fake-news
Spoiler: it’s fake news.
mikexcohen.substack.com/p/king-man-woman-queen-is-fake-news
"King - man + woman = queen" is fake news
On analogies and arithmetic inside LLM embeddings spaces.
mikexcohen.substack.com
October 13, 2025 at 9:50 PM
“King – man + woman = queen” sounds smart until you actually check the math.
Spoiler: it’s fake news.
mikexcohen.substack.com/p/king-man-woman-queen-is-fake-news
Spoiler: it’s fake news.
mikexcohen.substack.com/p/king-man-woman-queen-is-fake-news
Do straight lines exist?
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
Do straight lines exist?
Do lines even exist outside our imaginations?
open.substack.com
October 9, 2025 at 7:00 PM
Do straight lines exist?
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
I don't know what's going on in this AI image.
But I do know this: Daily Data Challenge #25 is short and very practical for data science. You'll get to create a symmetric matrix and extract its unique elements.
Can you solve it in less than 6 minutes?
mikexcohen.substack.com/p/ddc-25-uni...
But I do know this: Daily Data Challenge #25 is short and very practical for data science. You'll get to create a symmetric matrix and extract its unique elements.
Can you solve it in less than 6 minutes?
mikexcohen.substack.com/p/ddc-25-uni...
October 8, 2025 at 6:09 PM
I don't know what's going on in this AI image.
But I do know this: Daily Data Challenge #25 is short and very practical for data science. You'll get to create a symmetric matrix and extract its unique elements.
Can you solve it in less than 6 minutes?
mikexcohen.substack.com/p/ddc-25-uni...
But I do know this: Daily Data Challenge #25 is short and very practical for data science. You'll get to create a symmetric matrix and extract its unique elements.
Can you solve it in less than 6 minutes?
mikexcohen.substack.com/p/ddc-25-uni...
Here’s a picture of Thalorion The Destroyer reading my calculus textbook. I hope he likes it! Otherwise he might unleash doom on humanity.
www.amazon.com/dp/B0DX6BPPZ8
www.amazon.com/dp/B0DX6BPPZ8
October 7, 2025 at 2:06 PM
Here’s a picture of Thalorion The Destroyer reading my calculus textbook. I hope he likes it! Otherwise he might unleash doom on humanity.
www.amazon.com/dp/B0DX6BPPZ8
www.amazon.com/dp/B0DX6BPPZ8
Karl Gauss (yeah, *that* Gauss) sent me a fax this morning to say that he really enjoyed working through today's Daily Data Challenge.
mikexcohen.substack.com/p/ddc-23-dis...
mikexcohen.substack.com/p/ddc-23-dis...
DDC-23: Distributions of MNIST pixel values
A data challenge a day helps you master machine learning
mikexcohen.substack.com
October 4, 2025 at 5:55 AM
Karl Gauss (yeah, *that* Gauss) sent me a fax this morning to say that he really enjoyed working through today's Daily Data Challenge.
mikexcohen.substack.com/p/ddc-23-dis...
mikexcohen.substack.com/p/ddc-23-dis...
Why I left academia and neuroscience.
This post on Substack has gained a lot of traction. I think many people identify with it.
(Most of my posts are technical tutorials on machine-learning and LLM-mechanisms.)
mikexcohen.substack.com/p/why-i-left...
This post on Substack has gained a lot of traction. I think many people identify with it.
(Most of my posts are technical tutorials on machine-learning and LLM-mechanisms.)
mikexcohen.substack.com/p/why-i-left...
Why I left academia and neuroscience
Don't worry, this isn't yet another story of rage-quitting.
mikexcohen.substack.com
October 2, 2025 at 1:00 PM
Why I left academia and neuroscience.
This post on Substack has gained a lot of traction. I think many people identify with it.
(Most of my posts are technical tutorials on machine-learning and LLM-mechanisms.)
mikexcohen.substack.com/p/why-i-left...
This post on Substack has gained a lot of traction. I think many people identify with it.
(Most of my posts are technical tutorials on machine-learning and LLM-mechanisms.)
mikexcohen.substack.com/p/why-i-left...
Daily Data Challenge 8: Test for Pythagorean triplets
A data challenge a day helps you master machine learning.
More exercises and solutions at mikexcohen.substack.com
youtube.com/shorts/LlqS2...
A data challenge a day helps you master machine learning.
More exercises and solutions at mikexcohen.substack.com
youtube.com/shorts/LlqS2...
Daily Data Challenge 8: Test for Pythagorean triplets
YouTube video by Mike X Cohen
youtube.com
October 1, 2025 at 6:56 PM
Daily Data Challenge 8: Test for Pythagorean triplets
A data challenge a day helps you master machine learning.
More exercises and solutions at mikexcohen.substack.com
youtube.com/shorts/LlqS2...
A data challenge a day helps you master machine learning.
More exercises and solutions at mikexcohen.substack.com
youtube.com/shorts/LlqS2...
Bootstrapping: because sometimes asking “what if?” 10,000 times is a valid math strategy.
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
Confidence intervals 2/3: bootstrapping methods
Learn computational statistics in the second part of this three-part series.
open.substack.com
September 27, 2025 at 6:16 AM
Bootstrapping: because sometimes asking “what if?” 10,000 times is a valid math strategy.
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
genAI never fails to deliver the laughs.
September 27, 2025 at 6:08 AM
genAI never fails to deliver the laughs.
Daily Data Challenges are going strong.
Today's challenge is to create this beautiful graph using numpy and matplotlib. Can you do it?
mikexcohen.substack.com/p/ddc-18-err...
Today's challenge is to create this beautiful graph using numpy and matplotlib. Can you do it?
mikexcohen.substack.com/p/ddc-18-err...
September 26, 2025 at 11:03 AM
Daily Data Challenges are going strong.
Today's challenge is to create this beautiful graph using numpy and matplotlib. Can you do it?
mikexcohen.substack.com/p/ddc-18-err...
Today's challenge is to create this beautiful graph using numpy and matplotlib. Can you do it?
mikexcohen.substack.com/p/ddc-18-err...
This is not a skeet.
mikexcohen.substack.com/p/this-is-no...
mikexcohen.substack.com/p/this-is-no...
This is not a post
Will pipes exist in 100 trillion years?
mikexcohen.substack.com
September 26, 2025 at 11:01 AM
This is not a skeet.
mikexcohen.substack.com/p/this-is-no...
mikexcohen.substack.com/p/this-is-no...
Have you done your Daily Data Challenge?
mikexcohen.substack.com/p/ddc-8-test...
mikexcohen.substack.com/p/ddc-8-test...
September 12, 2025 at 5:10 AM
Have you done your Daily Data Challenge?
mikexcohen.substack.com/p/ddc-8-test...
mikexcohen.substack.com/p/ddc-8-test...
People talk a lot about GPT5 and hallucinations and trust and so on.
But let's not forget that GPT2 is the ultimate arbiter of truth and science.
Proof of my claim? This zinger from GPT2.
Wanna explore GPT2's wisdom in your own private Python session? mikexcohen.substack.com/p/lessons-on...
But let's not forget that GPT2 is the ultimate arbiter of truth and science.
Proof of my claim? This zinger from GPT2.
Wanna explore GPT2's wisdom in your own private Python session? mikexcohen.substack.com/p/lessons-on...
September 11, 2025 at 2:17 PM
People talk a lot about GPT5 and hallucinations and trust and so on.
But let's not forget that GPT2 is the ultimate arbiter of truth and science.
Proof of my claim? This zinger from GPT2.
Wanna explore GPT2's wisdom in your own private Python session? mikexcohen.substack.com/p/lessons-on...
But let's not forget that GPT2 is the ultimate arbiter of truth and science.
Proof of my claim? This zinger from GPT2.
Wanna explore GPT2's wisdom in your own private Python session? mikexcohen.substack.com/p/lessons-on...
GPT2 is hilarious.
September 10, 2025 at 11:22 AM
GPT2 is hilarious.
Dear bluesky neuroscientists: You should pay attention to the field of LLM mechanistic interpretability.
Not because LLMs are like real brains (they are absolutely nothing alike), but because mech interp analysis methods would be useful in neuroscience.
Start learning here: tinyurl.com/48pum4pb
Not because LLMs are like real brains (they are absolutely nothing alike), but because mech interp analysis methods would be useful in neuroscience.
Start learning here: tinyurl.com/48pum4pb
LLM breakdown 1/6: Tokenization (words to integers)
Large language models can't read; instead, they are given numbers that come from text.
mikexcohen.substack.com
September 10, 2025 at 9:07 AM
Dear bluesky neuroscientists: You should pay attention to the field of LLM mechanistic interpretability.
Not because LLMs are like real brains (they are absolutely nothing alike), but because mech interp analysis methods would be useful in neuroscience.
Start learning here: tinyurl.com/48pum4pb
Not because LLMs are like real brains (they are absolutely nothing alike), but because mech interp analysis methods would be useful in neuroscience.
Start learning here: tinyurl.com/48pum4pb
One of my fav quotes: "The way you do anything is the way you do everything."
The problem with these pithy faux-philosophical quotes is that they don't stand up to scrutiny. For example, I definitely do not pick my nose with the same rigor, depth, and intensity with which I write 600-page textbooks
The problem with these pithy faux-philosophical quotes is that they don't stand up to scrutiny. For example, I definitely do not pick my nose with the same rigor, depth, and intensity with which I write 600-page textbooks
September 9, 2025 at 11:17 AM
One of my fav quotes: "The way you do anything is the way you do everything."
The problem with these pithy faux-philosophical quotes is that they don't stand up to scrutiny. For example, I definitely do not pick my nose with the same rigor, depth, and intensity with which I write 600-page textbooks
The problem with these pithy faux-philosophical quotes is that they don't stand up to scrutiny. For example, I definitely do not pick my nose with the same rigor, depth, and intensity with which I write 600-page textbooks
Can you code the Fourier transform from scratch?
I bet you can. Spend 20 minutes on the Substack post, and you'll learn everything you need to understand and code the FT in Python.
mikexcohen.substack.com/p/the-fourie...
I bet you can. Spend 20 minutes on the Substack post, and you'll learn everything you need to understand and code the FT in Python.
mikexcohen.substack.com/p/the-fourie...
September 8, 2025 at 5:25 PM
Can you code the Fourier transform from scratch?
I bet you can. Spend 20 minutes on the Substack post, and you'll learn everything you need to understand and code the FT in Python.
mikexcohen.substack.com/p/the-fourie...
I bet you can. Spend 20 minutes on the Substack post, and you'll learn everything you need to understand and code the FT in Python.
mikexcohen.substack.com/p/the-fourie...
Do you have enough confidence?
I am, of course, talking about confidence intervals, the statistical measure of uncertainty around a sample characteristic like the average or correlation.
Here's my latest series on Substack about confidence intervals: mikexcohen.substack.com/p/confidence...
I am, of course, talking about confidence intervals, the statistical measure of uncertainty around a sample characteristic like the average or correlation.
Here's my latest series on Substack about confidence intervals: mikexcohen.substack.com/p/confidence...
Confidence intervals 1/3: interpretation and equation
Start building confidence about confidence intervals in the first of this three-part series.
mikexcohen.substack.com
September 8, 2025 at 10:29 AM
Do you have enough confidence?
I am, of course, talking about confidence intervals, the statistical measure of uncertainty around a sample characteristic like the average or correlation.
Here's my latest series on Substack about confidence intervals: mikexcohen.substack.com/p/confidence...
I am, of course, talking about confidence intervals, the statistical measure of uncertainty around a sample characteristic like the average or correlation.
Here's my latest series on Substack about confidence intervals: mikexcohen.substack.com/p/confidence...
Daily data challenge. 10 minutes a day to improve your coding, data science, and visualization skills.
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
September 6, 2025 at 7:51 PM
Daily data challenge. 10 minutes a day to improve your coding, data science, and visualization skills.
open.substack.com/pub/mikexcoh...
open.substack.com/pub/mikexcoh...
Happy teacher's day (in India)!
September 5, 2025 at 7:20 AM
Happy teacher's day (in India)!