Zekun Blog

Building and evaluating AI-powered products, agent systems, and local-first developer tools.

LAPOP Data Dashboard

A dashboard prototype built with Shiny R

This project is a data visualization dashboard designed to help non-professional users explore the Latin American Public Opinion Project (LAPOP). Due to copyright issues and confidentiality agreem...

Posted by Zekun Wang on February 19, 2020

Cashbox Magazine Song Chart Analysis

A simple example of a data analysis pipeline

This article introduces the full picture of a data analysis pipeline by showing simple data import, feature engineering, and exploratory data analysis processes. The data used here is relatively ...

Posted by Zekun Wang on February 15, 2020

Think Strategically and Get Jobs - H1B Visa Analysis

Helping international data science students strategize their job search

H1B The H1B visa is a non-immigrant visa that allows companies in the US to hire graduate-level workers in specialty occupations that require theoretical or technical expertise in specialized fie...

Posted by Zekun Wang, Yasi, Yilin, Ali on December 12, 2019

As data scientists, what should we do?

Data science application analysis, using product launch processes as an example

Slides Summary Three major parts of data science work: Use EXPLORATION to turn the unknown into the known. Use INFERENCE to help find something new from the old. Use PREDICTION to make be...

Posted by Zekun Wang on December 11, 2019

Power and Sample Size Calculations for Correlational Studies

Probability and Statistical Inference - 10

A common research objective is to demonstrate that two measurements are highly correlated. One measurement, call it A, may reflect the severity of disease but is difficult or costly to collect. Ano...

Posted by Zekun Wang on November 22, 2019

Central Limit Theorem - Approximation

Probability and Statistical Inference - 09

Import the packages first. library(magrittr) library(sn) Situation Description The central limit theorem is an important computational shortcut for generating and making inferences from the samp...

Posted by Zekun Wang on November 12, 2019

What makes a trending video?

An analysis of trending YouTube videos

Slides Introduction YouTube is one of the biggest media platforms of the 21st century. 5 Billion videos are watched daily. 500 Hours of videos are uploaded every minute. 51% of users say that...

Posted by Zekun Wang, Ali, Mingli on October 29, 2019

Simulation Method Comparison

Probability and Statistical Inference - 08

Situation Description This time, I will perform a $2 \times 4 \times 2$ factorial simulation study to compare the coverage probability of various methods of calculating $90\%$ confidence intervals...

Posted by Zekun Wang on October 27, 2019

Coverage Probability of MLE

Probability and Statistical Inference - 07

Introduction In statistics, maximum likelihood estimation (MLE) is a method of estimating the parameters of a probability distribution by maximizing a likelihood function, so that under the ass...

Posted by Zekun Wang on October 15, 2019

Which quantiles of a continuous distribution can one estimate with more precision?

Probability and Statistical Inference - 05

Introduction The median is an important quantity in data analysis. It represents the middle value of a data distribution. Estimates of the median, however, have a degree of uncertainty because (a)...

Posted by Zekun Wang on September 18, 2019

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Building AI agent systems that can be evaluated, improved, and trusted.

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