usda-ree-ars.github.io/SEAStats

This page hosts learning materials for USDA ARS SEA statistics and data science trainings created by SEA area statistician Quentin Read. Please contact me if you have issues with accessibility of any of the content on these pages, or if you would like the source code of any of these materials.

For scientists interested in contacting me for a consultation, check out the frequently asked questions page!

To see a list of my favorite stats and R learning resources, check out the learning resources page.

For USDA personnel only: to access video recordings of previous training sessions, visit the SEA Statistics Training page on USDA Axon+ intranet.

R Installation instructions

Instructions for installing R, RStudio, and R packages

Follow these instructions before starting any of the lessons if you do not have R and RStudio installed on your laptop.

Instructions for setting up a Posit Cloud account

Follow these instructions if you are participating in a workshop using Posit Cloud to run R on a cloud server.


R Boot Camp lesson logo

R Boot Camp

Two 90-minute lessons on basic R programming for complete beginners (Lessons 1 and 2 in a six-lesson series).
Taught in hybrid format in Raleigh, NC, December 8-9, 2022, and in person in Fayetteville, AR, January 9, 2023; Booneville, AR, January 12, 2023; Stoneville, MS, June 14, 2023.

Full-text version Slides Worksheets Answers to Exercises
Lesson 1: R Boot Camp: the very basics Slides Worksheet Answers
Lesson 2: R Boot Camp: working with data frames Slides Worksheet Answers

A practical toolkit for mixed models lesson logo

A practical toolkit for mixed models in R

Four 90-minute lessons on fitting simple linear mixed models in R (Lessons 3-6 in a six-lesson series).
Taught in hybrid format in Raleigh, NC, December 8-9, 2022.

Full-text version Slides Worksheets Answers to Exercises
Lesson 3: From linear model to linear mixed model Slides Worksheet Answers
Lesson 4: Going further with mixed models Slides Worksheet Answers
Lesson 5: Generalized linear mixed models Slides Worksheet Answers
Lesson 6: Estimating and comparing treatment means Slides Worksheet Answers

Data visualization basics with R and ggplot2 lesson logo

Data visualization basics with R and ggplot2

90-minute session introducing students to visualizing data with R and ggplot2.
Taught in Fayetteville, AR, January 10, 2023; Athens, GA, February 8, 2023


A crash course in Bayesian mixed models with brms lesson logo

A crash course in Bayesian mixed models with brms

Three-hour session introducing students to Bayesian inference, and showing how to fit some simple Bayesian mixed models with brms.
Older versions taught in Fayetteville, AR, January 10, 2023; Athens, GA, February 9, 2023; and Stoneville, MS, June 16, 2023. Updated version taught in hybrid format in Raleigh, NC, December 8, 2023.


R for SAS users lesson logo

R for SAS Users

Three 90-minute lessons showing basic data processing and model fitting procedures in R and SAS side-by-side.
Lesson 1 taught in Athens, GA, February 7, 2023. Lessons 1 and 2 taught in Stoneville, MS, June 14-15, 2023.

Full-text version Slides R Code Worksheet SAS Code from Lesson Answers to Exercises
Lesson 1: Basic R for SAS users Slides Worksheet Lesson SAS code file Answers
Lesson 2: Intro to Mixed Models in R for SAS users Slides Worksheet Lesson SAS code file Answers
Lesson 3: My first GLMMs in R for SAS users Slides Worksheet Lesson SAS code file Answers

Other stats and data science talks

I have given talks on a wide range of topics in stats and data science to different scientific audiences. I’ve provided the lecture slides as PDF or HTML files here. Video recordings of some of these talks are available on the Axon+ page (USDA personnel only).

Talk (PDF slides) Date Venue
(Un)ethical practices in biostatistics February 28, 2023 NCSU Biotechnology guest lecture, Raleigh, NC
Power analysis: bureaucratic busywork or critical part of the scientific method? July 25, 2023 IACUC workshop, Athens, GA (virtual)
Structural equation modeling in food science August 1, 2023 FSMQHRU unit meeting, Raleigh, NC
Statistical interactions: what are they and what do they mean, anyway? January 8, 2024 MMRU & Arkansas Children’s Nutrition Center, Little Rock, AR
Everything you ever wanted to know about means comparisons but were afraid to ask January 10, 2024 DBNRRC, Stuttgart, AR
Troubleshooting common errors and warnings in (G)L(M)Ms January 11, 2024 DBNRRC, Stuttgart, AR
Bayesian p-values!?!? January 18, 2024 USDA ARS statisticians’ monthly meeting
A smorgasbord of options for multiomics data analysis January 9, 2024 MMRU & Arkansas Children’s Nutrition Center, Little Rock, AR

Archived course and workshop pages

These are the homepages for stats trainings I have held in the past in case anyone needs to refer to them. They include the syllabi for the workshops, with links to the text and slides versions of the lessons I taught, as well as the worksheets and example datasets.

This page last updated by QDR on 2024-01-18. This page’s contents were created by the author and do not reflect official USDA policy.