What a fantastic e-mail I received this past year. It combines two wonderful things – money, and people wanting to send money to me. But this money was coming from a very special place.

In 2017, a talented, driven group of students at my high school participated in the Moody’s Mega-Math Challenge. In this annual math modeling contest students are provided a prompt and 14 hours to develop a framework for a solution. The contest is now sponsored by MathWorks, and you can learn about the contest and resources for getting your students involved at the contest website. The team earned an honorable mention award for their solution – and a $1,000 prize to be split amongst the team members. Not a bad way to close out their math careers in our district, and on to bigger and better things!

Jack enrolled at Dartmouth University in the fall of 2017. Like most students who move on to college, I had limited contact with Jack after he left high school. And similar to many of my colleagues here who were part of Jack’s life, I was gutted when I learned of his passing in 2019.

Fast-forward to last spring, when the nice folks at the Society for Industrial and Applied Mathematics informed me that 2 years after winning his prize for the modeling contest, Jack hadn’t cashed the prize check. After contacting his family, the funds were donated to the high school math club. A wonderful gesture, but math club really doesn’t require much funding….so what to do with found money? How best to honor Jack’s legacy at our school?

Chess.

I’m not sure what percentage of Jack’s down time at our high school was spent playing chess, or even how much time was spent playing chess when he was supposed to be working on something else, but it was a solid amount. But if you observed Jack playing chess you quickly realized the game was secondary. Having a conversation, thinking deeply, learning about someone new – these were the important residuals of a chess board.

I used the donated money to purchase as many nice-ish chess boards as possible and worked with our HS guidance department to generate a list of teachers Jack worked with during his time in our district. This past week I organized 8 boards including a note about Jack encouraging players to make a new friend and enjoy a conversation through chess. Four of Jack’s former teachers received chessboard gifts, and classrooms all the way down to 4th grade will have a new set to enjoy. I hope the wonderful culture of caring about others and getting to know someone new through chess which Jack embraced will live on through these boards.

I hope you find these resources helpful for learning more about Jack and helping individuals and families in your own community who struggle with mental illness.

Thanks Jack.

]]>In my freshman-year Prob/Stat course, students experience a probability lesson featuring the game “Egg Roulette”, based on a bit from Jimmy Fallon’s Tonight Show. Here is a summary of the “live” lesson: https://mathcoachblog.com/2015/09/20/an-egg-cellent-simulation/. This year, there were two considerations for how I would have students investigate the game: conducting the simulation and collecting the results.

**CONDUCTING THE SIMULATION**

The first class simulation involves two unsuspecting volunteers and my actual container of 12 “eggs” – filled with little fuzzballs. Click the link in the last paragraph to see a video of how it works. In the main simulation, students use decks of cards to play the game repeatedly. Give pairs of students 13 cards all of the same suit. Discard the ace. Then, the 10, jack, queen and king represent “raw” eggs. The other cards represent the “hard-boiled” eggs. In a remote environment I could have used a site like random.org to draw cards, but I also saw an opportunity to build a simulation students could use to quickly analyze repeatedly. This Desmos link allows students to play the many times: https://www.desmos.com/calculator/2b7f6p4r3o. Click the “rerandomize” button to generate repeated plays of the game. Online, we talked through a few of the simulations and I found the students quickly understood the format.

**COLLECTING THE RESULTS**

I have used a number of methods for collecting class results over the year: sticky dots on a poster, Post-It Notes on a wall, digital data collection. Clearly this year we had to go digital, and the site http://stapplet.com came to the rescue. New this year, teachers have a “collaborative” option – this feature generates a class code from which students can submit their data to the class (thanks Josh Tabor and Luke Wilcox!). The results update in real time. Each student then pasted the class graph into OneNote and a discussion of Jimmy Fallon’s “meanness” – is he being nice to his guests by letting them draw first? – followed.

The rest of the lesson and discussion felt similar to previous years. I challenge small groups to find the probability of a player losing in round 3. This leads us to probability ideas of independence / dependence and the multiplication rule. The engagement remained high and the conversation was on par with previous years!

]]>The first thing I noticed about the updated editor was the increased freedom in screen design. Previously, elements like Graph, Note and Input were limited in their placement and number. There is more freedom now to move elements around, order them as you like, and include more of them in a single screen.

Immediately I wanted to explore this new freedom and think about intentionality in my design process for an activity I wrote and used in my AP Stats class this spring – Is My Die Fair. In this activity students “roll” both a virtual hand-made die and a virtual real die. The activity allows students to discover the chi-squared statistic as a reasonable measure of variability in a categorical distribution. Here are two ways I changed this activity with the new editor, with the intent that students will be able to follow the narrative with less arrowing through the activity.

**ORIGINAL VERSION:**

Screen 2: students roll the hand-made die 60 times

Screen 3: results are copied from screen 2 and students make observations.

**NEW VERSION:**

Students roll the die AND make a conjecture on the same screen.

Another place I was able to leverage the new block placement freedom occurred later when students begin to think about the computation of the chi-squared statistic.

**ORIGINAL VERSION:**

Screen 8: the new statistic is explained, and students complete a table for the homemade die only.

Screen 9: a summary statistic is shown, and students now complete the table for the real die.

Screen 10: both summary statistics are shown and students make a final conjecture about the dice.

**NEW VERSION:**

Screen 7: the new statistic is explained, and students complete tables for both types of dice on the same screen.

Screen 8: both summary statistics are shown and students make a final conjecture about the dice.

Share your ideas for altering your previous activities to leverage the new design freedoms. Below, you can test-drive both activities and see how I altered them. Your ideas are always appreciated…now get building!

“Is My Die Fair” – original version – https://teacher.desmos.com/activitybuilder/custom/5e713346f6e84e7dd46727fd

“Is My Die Fair” – version 2 –https://teacher.desmos.com/activitybuilder/custom/5ef38c6cad9e310dc0a6ac23

]]>I applied for the Rosenthal Prize back in the spring. At that time I looked back at old blog posts for lessons which seemed to be of interest and use to teachers, and chose one which has generated many positive comments: the 35 Game. The original post describes the game and how to leverage the results to build need for compound inequalities: https://mathcoachblog.com/2016/01/07/the-35-game-for-compound-inequalities/

I was thrilled to find out later in the year that my lesson was chosen as a Finalist for the award, but then the hard work begins. There is quite a lot to submit for this prize including:

- A complete lesson plan
- A video of the lesson in action
- 3 recommendation letters

Every year the “35 Game” seems to get many blog hits and comments from teachers who use it. I am hoping that sharing my lesson plan write-up with the math community will provide guidance and usefulness to those teachers who enjoy this lesson. Any feedback you have is appreciated!

Thanks to my friends and colleagues Dennis Williams, DJ Fromal and David Weber for their willingness to provide recommendation letters. I work with inspiring and wonderful educators!

]]>**ASSESSING NORMALITY** (Here is a previous post on this topic)

Pop quiz! Below you see 6 boxplots. Each boxplot represents a random sample of size 20, each drawn from a large population. Which of the underlying populations have an approximately normal shape? Take a moment to think how you…and your students…might answer…

Have your answers ready? Here comes the reveal…..

Not only do each of the samples above come from normal populations, they each come from the same theoretical population! This year in class I plan to walk students through how to build their own random sampler on Desmos, which takes only a few intuitive commands. When the “random” command is used, we now get a re-randomize” button which allows students to cycle through many random samples and assess the shapes. You can toy with my graph here.

Often students look for strict symmetry or place too much stock in different-sized tails. This is a great opportunity to have students explore and understand the variability in sampling. Teach your students to widen their nets when trying to assess normality and remember – our job is usually not to “prove” normality; instead, these samples show that the assumption of population normality is often safe and reasonable, especially with small samples.

LI**NEAR TRANSFORMATIONS OF DATA**

Analyzing univariate data using Desmos is now quite easy. Let your students build and explore their own data sets. Data can be either typed in as a list or imported from a spreadsheet using copy/paste. The command “Stats” provides the 5-number summary, and commands for mean and standard deviation are also available. You can play around with my dataset here.

Next, I want my students to consider transformations to the data set. In my example I have provided a list of test scores and summary statistics are provided. Let’s think about a “what if”. In the next lines I provide 2 boxplot commands, but I have intentionally ruined the command by placing an apostrophe before the command (thanks Christopher Danielson for this powerful move!). What will happen if every student is given 5 “bonus” points? What if I feel generous and add 10% to everyone’s grade?

What will happen when I remove those apostrophes? Think about the center, shape and spread of the resulting boxplots? How will these new boxplots be similar to and different from the original?

Compute new summary statistics. Which stats change…by now much…and what stays the same? Why? I’m looking forward to having students build their own linear transformation graphs, investigating and summarizing their findings! Here is a graph you can use with your classes to explore these linear transformations with sliders.

**COMBINATIONS OF DISTRIBUTIONS**

An important topic later in AP Stats – what happens when we combine distributions by adding or subtracting? Often I will use SAT scores as a context to introduce this topic because there are two sections (verbal and math) and a built-in need to add them – What are the total scores? On which section do students tend to do “better”…and by how much? To build a Desmos interactive here, I start with a theoretical normal distribution with mean 500 and standard deviation 100 to represent both mean and verbal score distributions. Next, taking 2 random samples of size 1000 and building commands to add and subtract them allows us to look at distributions of sums and differences and compare their center, shape and spread.

The most important take-away for students here should be that distributions of sums and differences have similar variability. This is a tricky, yet vital, idea for students as they begin to think about hypothesis tests for 2 samples. You can use my graph, or build your own. Note – in my graph the slider is used to generate repeated random samples.

]]>- Desmos Support – General Statistics Functions
- MLB data set
- AP Exam 2019 #1 Data
- AP Exam 2019 #5 Scenario
- 2-Dice Simulation
- Bob’s Activity Collection – aligned to TPS4e

The preliminary lineup of speakers appears in the file below. With Keynotes by Dan Meyer and Robert Berry, a Desmos pre-conference the day before, and our first ever trivia night, it’s going to be a great 2 days in Harrisburg!

Register today and get all the details:

https://www.eventbrite.com/e/pctm-annual-conference-registration-52503521446

I recalled reading about a potential golf-related task on twitter. To be honest, I don’t recall whose exact post provided the inspiration here (note – I am thinking it was Robert Kaplinsky or John Stevens, but I may be wrong. If anyone locates a source, I’ll edit this and provide ample credit), but it felt like a game-related task could provide by the strategy and fun elements which tend to be missed by drawing tasks.

**HOW THE GOLF CHALLENGE WORKS:**

The goal – write equations of lines which connect the “tee” to the “hole”. Use domain and/or range restrictions to connect your “shots”. Try to reach each hole in a minimal number of shots. Leaving the course (the green area) or hitting “water” are forbidden. All vertical or horizontal likes incur a one-stroke penalty.

On the day before the task, the class worked through a practice hole. Besides understanding the math task, there are also a few Desmos items for students to understand:

- Syntax for domain / range restrictions
- Placing items into folders
- Turning folders on /off

For the actual task, a shared a link to a Desmos file with 5 golf holes. I tried to build tasks which increased in their difficulty. In practice, the task took an entire class period (75 minutes), and students worked in pairs to discuss, plan, and complete the holes. All students then uploaded their graphs to Canvas for my review, and filled out a “scorecard” which included “par” for each hole. It became quite competitive and fun!

In the end, there is not too much I would change here. Perhaps add some more complex holes. I’d also like to provide opportunity for students to design and share their own golf holes, and study the “engine” which built mine. I hope your class has fun with it! Please share your suggestions, questions and adaptations.

]]>Challenge your students to list some things they notice and wonder about the graph, and visit the NYT August post to discover how teachers use WGOITG in their classrooms. Here are some ideas I have used before with my 9th graders:

- Have groups work in pairs to write a title and lede (brief introduction) to accompany the graph.
- Ask tables to develop a short list of bullet points facts which are supported by the graph, and share out on note cards.
- Have students consider how color, sizing, scaling are used in effective ways to support the story (note how the size of the arrows play a role in the graph shown here). This is a wonderful opportunity to think of statistics beyond traditional graphs and measures.

Invite your students to join in the moderated conversation, which drops on Thursday. Have your own favorite way to use WGOITG? Share it in the comments!

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Comparing Data Sets and Summary Statistics

Regression Facts (Mean/mean point and slope)

Teaching the meaning of r-squared

“Release the Hounds” – my first attempt at random sampling

Participate as a student, Steal and Share

“Backpack Weights” – thinking about scatterplots (AP Stats)

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