Posts by Year

2022

LKJCorr and LKJCov in pymc

9 minute read

While continuing to deep dive on covariance priors following my prior post, I investigated implementations in pymc. I played around with the LKJcorr and LKJc...

Escaping the Devil’s Funnel

7 minute read

Multi-level models are great for improving our estimates. However, the intuitive way these kinds of models are specified (which goes by the unhelpful name “c...

Correlated data, different DAGs

5 minute read

One of the lessons from Statistical Rethinking that really hit home for me was the importance of considering the data generation process. Different datasets ...

Running models forwards and backwards

7 minute read

The value of simulations is highighted by Dr. McElreath throughout his textbook and by van de Schoot and colleagues. I didn’t entirely appreciate its value u...

2021

Exploring modeling failure

20 minute read

In my last post, I gave an example of a multilevel model using a binomial generalized linear model (GLM). The varying intercept model helped illustrate pa...

Multilevel modeling with binomial GLM

14 minute read

I’ve been on a journey learning multilevel models and Bayesian inference through Richard McElreath’s Statistical Rethinking book. The concepts of shrinkage a...

Extending the chain

less than 1 minute read

Last month, I wrote about how I aimed to make daily contributions towards my goals, no matter how small. Not surprisingly, it has been challenging. Neverthel...

Vectorization with np.dot and broadcasting

4 minute read

Vectorization and broadcasting are tricks I have used sparingly and absent-mindedly if at all. However, it is a critical skill for algorithmic code to run ef...

The chain

1 minute read

Yesterday morning, I continued my habit of reading a chapter from the book Atomic Habits by James Clear. The chapter described the importance of showing up a...

PyMC linear regression part 1: PyMC objects

12 minute read

I previously wrote about my discovery of Statistical Rethinking. The book’s title could not be more spot-on–it’s helped me look at statistics in a different ...

Doing easy

1 minute read

I’ve struggled to write consistently. Part of the reason for this is because I’m prone to self-censorship. Even as I type this, my mind is talking to itself....

14 years

2 minute read

This site is about my data science journey but various posts indicate my love for baseball. It starts with my GitHub handle: benslack19. Let’s break it down....

Rethinking Bayes

7 minute read

A few weeks ago, I learned about the wonderful Statistical Rethinking lecture series and book by Richard McElreath. It’s made me think about some of the Baye...

Looking back and looking ahead

2 minute read

A year ago, I was anxious and excited about a planned life change. I had put in my notice and would start a data science program on January 13, 2020. I had b...

2020

Bayes-ball part 2: a more realistic prior

8 minute read

I meant to post this some time ago, but I have been busy. But with the baseball example I am using, it is only fitting that I post this now, just after this ...

Histograms and recursion in SQL

10 minute read

A few weeks ago, while making a histogram in a SQL query, I discovered that some solutions out there do not include bins with 0 counts. This bugged me so I f...

F-in statistics!

9 minute read

I recently read this passage in the section on multiple linear regression from the fantastic book Introduction to Statistical Learning:

PostgreSQL and Jupyter notebooks

1 minute read

PostgreSQL is one of the most popular variants of SQL. It is common to use PostgreSQL with pgadmin but I am not a big fan of their UI. By contrast, interacti...

Improving my writing

6 minute read

Introduction I have identified writing well as a skill I will prioritize. This improved skill will benefit both smaller forms I have taken for granted (like...

2019

Iterators in Python

3 minute read

One of the things about Python that I haven’t fully appreciated are the use of iterators. I’ll go over some iterators that are a part of base Python and then...

Heads or tails?

5 minute read

Seems like every statistics class starts off with a coin toss. It’s simple enough for me. Some fancy teachers might start right off the bat and get into the ...

2018

Applying logistic regression in Python

8 minute read

…from lessons learned from Andrew Ng’s ML course. Like other assignments of the course, the logistic regression assignment used MATLAB. Here, I translate MAT...

2015