# Tutorial

## SWIRL

Swirl teaches you R programming and data science interactively, at your own pace, and right in the R console!

## The t-distritbution and its normal approximation

I just published a new interactive visualization in my series of basic statistical concepts and techniques. This time I am trying to show how the t-distribution and the normal distribution differs, and how they become very similar for larger sample â€¦

## Tutorial/R code for creating funnel/forest plots

Meta-analyses are often accompanied by two popular forms of data visualization: forest plots and funnel plots. In this post, Iâ€™ll show how quick-and-dirty forest and funnel plots can be created with the metafor package. After, Iâ€™ll show how we can â€¦

## Tutorial/R code for creating plots for 2-way interactions

ggplot2, as Iâ€™ve already made clear, is one of my favourite packages for R. And since that original post about ggplot2 remains one of my most frequently visited, I thought I would proceed with starting a series of posts called â€śMake It Prettyâ€ť, all â€¦

## Tutorial/R code for creating scree/parallel analysis plots

With this post, Iâ€™m going to be showing how you can use the psych package in conjunction with ggplot2 in order to create a prettier scree plot with parallel analysisâ€“a very useful visualization when conducting exploratory factor analysis.

## Understanding Statistical Power and Significance Testing: an interactive visualization

Much has been said about significance testing â€“ most of it negative. Methodologists constantly point out that researchers misinterpret p-values. Some say that it is at best a meaningless exercise and at worst an impediment to scientific discoveries. â€¦

## Using R and lme/lmer to fit different two- and three- level longitudinal models

I often get asked how to fit different multilevel models (or individual growth models, hierarchical linear models or linear mixed-models, etc.) in R. In this guide I have compiled some of the more common and/or useful models (at least common in â€¦

## Visualizing a One-Way ANOVA using D3.js

A blog post and tutorial on visualizing one-way ANOVA