One year ago, I was living in Nashville, TN. Today, I live in São Paulo, Brazil. One year ago, I was teaching all girls. Mostly Southern US born-and-raised girls. Today, I am teaching both genders, from a variety of countries and backgrounds. One year ago, I was an AP Stats and geometry teacher. Today, IRead More

# Author: DavidGriswoldHH

## A better hierarchy?

Every year in April (well it actually used to be October, but that’s a story for another day), I teach quadrilaterals to my geometry students. And every year we make a “family tree” or “hierarchy” of quadrilaterals. The one we make in class is pretty basic – this year, it looks like this: Now, everyRead More

## Tchau, USA!

This will be my last year teaching in Nashville. My wife and I have made the huge decision to relocate (with all three of our kids) to São Paulo, Brazil next summer, where we will both be teaching at Graded International School (http://graded.br) for at least two years. I will still be teaching high schoolRead More

## First Day – very quick thoughts

This is almost a 180 blog post, except I forgot to take many pictures. 20 minute classes today. Pretty good! Geometry – three sections. Debated “What is a sandwich” and wrote definitions using this slide deck. Went super-well in all three classes and was lots of fun. Haven’t looked through the sandwich definitions they allRead More

## Some Geometry desmos activities and calculators

I just posted this as a new thread on the Geometry MTBoS forum, but I wanted to put it here too. If you teach geometry, come check out the forum! Some of us are hoping it will become a nice middle ground between the speed but temporary nature of Twitter and the more formal lessRead More

## How likely is any given study to be “true”? A conditional probability / inference exploration.

An important point I try to get across to students is that statistics is real math, but by its very nature statistical techniques always have a possibility of error. Which means that sometimes an experiment will find a “statistically significant” result (and therefore, in a super-simplistic view, result in a publishable paper in a respectedRead More

## Two kinds of experiments and their inference

This post is a continuation of sorts of my post the other day about using t-tests with experiments. I have been reading and researching all day, but I haven’t seen anybody really addressing the fact that there seem to be two different kinds of models for experiments that we treat the same, at least in AP Stats, butRead More

## Using t-tests and proportion z-tests with experiments

I am not a statistician, really. I took AP Statistics in high school (but never the exam) and a single statistics class in college as part of my core curriculum, but I never went further. So teaching it (and co-writing a book about it) for me, has been interesting – my grasp of What isRead More

## Always Sometimes Nevers are the best

Last year, I semi-accidentally created my single favorite geometry activity of the year: class-collaborated Always/Sometimes/Nevers. You can read about my initial version of the activity here if you’d like. The post this year is in two parts. In the first one, I talk about what I love about Always/Sometimes/Nevers as a problem type and the type ofRead More

## Bootstrap Confidence Intervals – not as reliable as their reputation!

I’ve been learning a lot about the deep details of statistics lately, motivated partially by interest and partially by a deep desire not to accidentally put something in the CPM Statistics book that is wrong! My current study is about bootstrapping confidence intervals. If you’ve never heard of bootstrapping, I’ll give you the introductory definition weRead More