Blog

Bootstrap vs Standard Error Confidence Intervals

A student recently asked whether bootstrap confidence intervals were more robust than confidence intervals estimated using the standard error (i.e. \(SE = \frac{s}{\sqrt{n}}\)…

ShinyQDA: R Package and Shiny Application for the Analysis of Qualitative Data

I will be giving a talk at ShinyConf 2025 on a Shiny application desiged for doing qualitative data analysis.

Sample size and statistical significance for chi-squared tests

In this post we are going to explore the relationship between sample size (n) and statistical significance for the chi-squared (\(\chi^2\)) test. Recall that from the normal…

Building a portfolio with Github and Quarto

Slides for a talk on how to build a portfolio website using Github

How many times do I need to take a test to randomly get all questions correct?

Darrin Rogers asked on Mastadon what are the “number of tries it would take, guessing randomly, to get 100% on a quiz if you had unlimited retries.” Here we will outline two…

login: User Authentication for Shiny Applications

The login package provides a framework for adding user authentication to Shiny applications. This is unique to other authentication frameworks such as ShinyManager and…

A Visual Introduction to Propensity Score Analysis

Recording of A Visual Introduction to Propensity Score Analysis given for the nyhackr meetup group.

Estimating Causality from Observational Data

The CUNY School of Professional Studies, Data Science and Information Systems department, is hosting a talk by Jason Bryer titled Estimating Causality from Observation Data. You can attend the talk in person at 119 West 31st Street, NY, New York, 10001 or watch the live stream. Please complete this form indicating your interest. Details on attending live or getting the Zoom link will be sent to the email address provided. Light refreshments will be provided for those attending in person.

R Package Development

Recording for an introduction to R package development.

Introduction to Shiny

Recording for an introduction to Shiny application development.

Map my run in R

First, I want to give a plug to the RStats Strava Running Club. If you are into running, it is a great group that provides lots of support.

Framework for Shiny Apps in R Packages

TL;DR: You can test this approach using this Github Gist.

Editable DataTables for Shiny Applications

RStudio recently updated Shiny to allow for editable DataTables. Their implementations allows for editing cells direclty with in the DataTable view. This is fine for many…

Conducting Assessments and Surveys with Shiny

This post describes a framework for using Shiny for conducting, grading, and providing feedback for assessments. This framework supports any multiple choice format including…

Shiny App for Bayes Billiards Problem

Consider a pool table of length one. An 8-ball is thrown such that the likelihood of its stopping point is uniform across the entire table (i.e. the table is perfectly…

Data Caching

Data caching is not new. It is often necessary to save intermediate data files when the process of loading and/or manipulating data takes a considerable amount of time. This…

Women Graduates in Math, Statistics, and Computer Information Systems

One of the more interesting talks at this year’s useR! Conference was the heR Panel discussing the role of women in the R community. They estimate that fewer than 15% of…

useR 2014 Slides for PSAboot and version 1.1. on CRAN

PSAboot is an R package to assist with bootstrapping propensity score methods. I gave a talk today at the useR! 2014 Conference. The slides can be downloaded from the…

str Implementation for Data Frames

The str function is perhaps the most useful function in R. It provides great information about the structure of some object. When I teach R, especially for those coming from…

Rgitbook Package for Using R Markdown with Gitbook

Last week I published an R script to interface with Gitbook. I received some positive feedback and decided to include all the code in an R package. This also allowed me to…

Albany, NY R Users Group

I have started an R Users Group for the Albany, NY area. Hopefully we get enough interest that we can host a meeting in the next couple of months. Please feel free to share…

Function to Simplify Loading and Installing Packages

One of the more tedious parts of working with R is maintaining my R library. To make my R scripts reproducible and sharable, I will install packages if they are not…

Bootstrapping for Propensity Score Analysis

I am happy to announce that version 1.0 of the PSAboot package has been released to CRAN. This package implements bootstrapping for propensity score analysis. This deviates…

Workshop and Talk Slides from NEAIR Conference

I am about to head home from my fifth time attending the North East Association for Institutional Research (NEAIR), this year in Newport, RI, which was just fantastic.…

Gambler’s Run with Shiny

I finally had an opportunity to play with Shiny, and I am very impressed. I have created a Github Project so head over there for the source code. There are a number of ways…

Cut Dates into Quarters

Frequently I need to recode a date column to quarters. For example, at Excelsior College we have continuous enrollment so we report new enrollments per quarter. To…

i Before e Except After c

When I went to school we were always taught the “i before e, except after c” rule for spelling. But how accurate is this rule? Kevin Marks tweeted today the following:

Converting a list to a data frame

There are many situations in R where you have a list of vectors that you need to convert to a data.frame. This question has been addressed over at StackOverflow and it turns…

Comparing two data frames with different number of rows

I posted a question over on StackOverflow on an efficient way of comparing two data frames with the same column structure, but with different rows. What I would like to end…

Version 1.0 of sqlutils available on CRAN

Version 1.0 of sqlutils has been released to CRAN. The sqlutils package is designed to manage a library of SQL files. This package grew out of the needs of an Office of…

Interactive SQL in R

I recently taught a very basic introduction to SQL workshop and needed a way to have participants interact with SQL statements. Obviously there are lots of tools to…

Reading Codebook Files in R

One issue I continuously encounter when starting to work with a new dataset is that of the codebook. In general, I prefer to load a codebook into R like any other data…

Function for Generating LaTeX Tables with Decimal Aligned Numbers

The xtable package is tremendously useful for generating LaTeX tables from data frames. It is also pretty easy to customize the output to handle some special cases of LaTeX…

Using (R) Markdown, Jekyll, & Github for a Website

Markdown has been growing in popularity for writing documents on the web. With the introduction of R Markdown (see also Jeromy Anglim’s post on getting started with R…

Fifty Shades of Grey in R

My wife went out to her book group tonight and their book of the month was 50 Shades of Grey. Sadly, I could think of is that plotting 50 shades in R would be a neat exercise.

Visualizing Missing Data

There are several graphics available for visualizing missing data including the VIM package. However, I wanted a plot specifically for looking at the nature of missingness…

User Input using tcl/tk

I was inspired by Kay Cichini recent post on creating a a tcl/tk dialog box for users to enter variable values. I am going to have a use for this very soon so took some time…

Graphic Parameters (symbols, line types, and colors) for ggplot2

Following up on John Mount’s post on remembering symbol parameters in ggplot2, I decided to give it a try and included symbols, line types, and colors (based upon Earl…

Given a room with n people in it, what is the probability any two will have the same birthday?

Revisiting a fun puzzle I remember first encountering as an undergraduate. Nice example of creating a plot in R using ggplot2. I also plot the probability of someone in the…

Object Oriented Programming in R

As someone who was a Java programmer for many years learning R’s object oriented programming framework has been frustrating to say the least. I like the simplicity of S3 but…

Retrieving RSS Feeds Using Google Reader

I have been working on a new package makeR to help manage Sweave projects where you wish to create multiple versions of documents that are based on a single source. For…

Visualizing Likert Items

I have become quite a big fan of graphics that combine the features of traditional figures (e.g. bar charts, histograms, etc.) with tables. That is, the combination of…