A tweet straight up solved a problem I encountered while teaching. The problem: How can I explain why the confidence interval area for a regression line is curved when the regression line is straight. This comes up when I use my favorite regression example.  It explains regression AND the power that government funding has over academic research . TL:DR- Relative to the number of Americans who die by gun violence, there is a disproportionately low amount of a) federal funding and b) research publications as to  better understand gun violence death when compared to funding and publishing about other common causes of death in America. Why? Dickey Amendment to a 1996 federal spending bill. See graph below: https://jamanetwork.com/journals/jama/article-abstract/2595514 The gray area here is the confidence interval region for the regression line. And I had a hard time explaining to my students why the regression line, which is straight, doesn't have a perfectly rectangula...

So, Fortnite is a super popular, first-person-shooter, massive multi-player online game. I only know this because my kid LOVES Fortnite. With the free version, called Battle Royale, a player parachutes onto an island, scour for supplies, and try to kill the other players. Like, there is way more to it than that, but this is my limited, 39-year-old mother of two explanation. And, admittedly, I don't game, so please don't rake me over the coals if I'm not using the proper Fortnite terminology to describe things! Anyway, my brain thinks in statistics examples. So I noticed that for each Battle Royale match starts with 100 players. See the screen shot: This player is parachuting on to the island at the beginning of the skirmish, and there are still 100 players left since the game is just starting and no one has been eliminated. Well, when we introduce our students to the normal curve and percentiles and z-scores and such, we tell them that the normal curve represen...

Patti Neighmond, reporting for NPR, wrote a piece on how the medical establishment's method for assessing patient pain is evolving . This is a good example of why it can be so tricky to operationalize the abstract. Here, the abstract notion in pain. And the story discusses shortcomings of the traditional numeric, Wong-Baker pain scale, as well as alternatives or complements to the pain scale. No one is vilifying the scale, but recent research suggests that what a patient reports and how a medical professional interprets that report are not necessarily the same thing. From Dr. John Markman's unpublished research: I think this could also be a good example of testing for construct validity. The researcher asked if the pain was tolerable and found out that their numerical scale was NOT detecting intolerable. This is a psychometric issue. One of the recommendations for better operationalization: Asking a patient how pain effects their ability to perform every day tas...

I'm such a sucker for beer-related statistics examples ( 1 , 2 , 3 ). Here is example 4. Now, I don't know about the rest of you psychologists who teach statistics, but I ALWAYS show the ol' Yerkes-Dodson's graph when explaining that correlation ONLY detects linear relationships but not curvilinear relationships. You know...moderate arousal leads to peak performance. See below: http://wikiofscience.wikidot.com/quasiscience:yerkes-dodson-law BUT NOW: I will be sharing research that finds claims that dementia is associated with NO drinking...and with TOO MUCH drinking...but NOT moderate drinking. So, a parabola that Pearson's correlation would not detect.  https://twitter.com/CNN/status/1024990722028650497