Publications by Nicole Radziwill
Pareto Charts in R
A Pareto Chart is a sorted bar chart that displays the frequency (or count) of occurrences that fall in different categories, from greatest frequency on the left to least frequency on the right, with an overlaid line chart that plots the cumulative percentage of occurrences. The vertical axis on the left of the chart shows frequency (or count), a...
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Bar Charts and Segmented Bar Charts in R
Here are a couple of tutorials I’ve written to help anyone who’s interested in learning how to produce simple bar charts or simple segmented bar charts in R, given that you have some data stored in a CSV file that you can use. Please leave any comments if there are ways I can make this information more clear and useful. Thanks! bar-charts-75-...
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Normal Probability Plots (QQ Plots) in R
Here’s a tutorial on how to tell whether your data are (approximately) normally distributed! qq-plot-75-925 Related To leave a comment for the author, please follow the link and comment on their blog: Quality and Innovation » R. R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. ...
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Text Analysis Tutorial on Spam Email in R
Hi everyone – I just wrote a tutorial on text analysis in R using the tm and wordcloud packages. Thought some of you here might be interested in it: text-analysis-75-925 Related To leave a comment for the author, please follow the link and comment on their blog: Quality and Innovation » R. R-bloggers.com offers daily e-mail updates about...
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Top 20 Data Visualization Tools
Editor’s note: the original link in this post was changed, here is the update link to “The 36 best tools for data visualization” ————– Every researcher or practitioner of quality (or pretty much any other subject, for that matter) needs a great toolbox packed with flexible visualization tools. I am very happy to see this list o...
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Analyzing Monthly Expenses with a Pareto Chart
This month, ASQ CEO Paul Borawski encourages us to share stories about “quality solutions in unexpected places.” This is such a fun question, because now I’ll be noticing these unexpected gems all month – and probably beyond! Today’s gem comes from my former student Andy, who has heard me get excited about quality tools and continuous...
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Contingency Tables with gmodels in R
Contingency tables provide a way to display the frequencies and relative frequencies of observations, which are classified according to two categorical variables. The elements of one category are displayed across the columns; the elements of the other category are displayed over the rows. For many semesters now, I’ve asked my students to pre...
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A Linear Congruential Generator (LCG) in R
In my simulation classes, we talk about how to generate random numbers. One of the techniques we talk about is the Linear Congruential Generator (LCG). Starting with a seed, the LCG produces the first number in the sequence, and then uses that value to generate the second one. The second value is used to generate the third, the third to generate ...
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Why the Ban on P-Values? And What Now?
Just recently, the editors of the academic journal Basic and Applied Social Psychology have decided to ban p-values: that’s right, the nexus for inferential decision making… gone! This has created quite a fuss among anyone who relies on significance testing and p-values to do research (especially those, presumably, in social psychology who we...
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One-proportion z test in R
For quite a while, I’ve been confused by the behavior of the prop.test function in R: 1) the p-values always seem to be slightly off, and 2) the confidence intervals never seem to be symmetric around my estimate of the population proportion. Today, I decided I was going to figure out what was up… and whether I should trust my own analytical...
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