Omitted Variable Bias by Simulation

Overview In simulation, we can show that omitting a variable \(x_2\) can cause the point estimates for a correlated variable \(x_1\) to change from (positive) \(0.999\) with a p-value of nearly zero, to (negative!) \(-0.512\), also with a p-value of nearly zero! More generally, this reinforces the mantra that unless...

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Moving Average in R, tidyverse

Problem Given some dataset, you might want to find the rolling or moving average. We can visualize this in a sample dataset as follows. Note, the k-lag moving average we want, MA-k, is the mean of the last k observations in time, including the current one. # A tibble: 48...

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Build a Neural Network with Julia

Audience If you’re reading this, I assume you are already motivated to learn how a neural network actually works. They are relevant and powerful tools, so the sell shouldn’t be too difficult anyway. There are many other excellent guides out there that I will link to below. If you find...

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A blog on data, prediction, and causal inference.