Grading Code with gradethis by Dan Chen. Visit https://rstats.ai/nyr/ to learn more. Bio: Daniel Chen is a PhD student in the interdisciplinary PhD program in Genetics, Bioinformatics & Computational Biology (GBCB) at Virginia Tech. He utilizes data and statistical models to study the spread of disease and the efficacy of medicine and treatments. He holds a masters in Epidemiology from Columbia University and earned his bachelor degree in Psychology from the Macaulay Honors College at CUNY Hunter College with a concentration in behavioral neuroscience and minors in computer science and biology. Daniel specializes in research design, analysis and teaching scientific computing with an emphasis on R, Git, Python and Linux. Currently focused on the study of population health using a data science approach through agent-based modeling. Daniel is the author of Pandas for Everyone, an expansion in the Pearson series---the Python/Pandas complement to R for Everyone. Twitter: https://twitter.com/chendaniely Presented at the 2020 R Conference | New York (August 14th, 2020)