Asked & Answered 7.0

You are the first-year coach of the Texas Lady Longhaulers of the WNBA.  This morning finds you dispirited after an embarrassing 88-60 loss to the Nashville Wynettes last night.  You need a more productive starting lineup for tomorrow’s game.  Where to begin?

Point guard is your most important position and your roster choices are Maya Thomas and Tamika DeShields.  They are good but very different players.  Maya is a steady shooter who has a 50% chance of sinking each shot.  Tamika, on the other hand, is streaky: if she sinks a shot, she makes her next one 80% of the time; but if she misses, she tends to miss again, 80% of the time.

So which point guard would you start, Steady Maya or Streaky Tamika?

I thought I would make this edition of Asked and Answered more interactive than usual. Readers, before I begin the discussion, you are invited to weigh in with your own answer. On the form below, check the box for either Steady, Streaky, no difference, or it depends.  There are no penalties for incorrect answers so just go ahead and check the box that your first-year-coaching gut tells you is the best one.  Then click the Vote button to record your answer and view the totals so far.

Coming Soon
The Better Player: Steady or Streaky?
The Better Player: Steady or Streaky?
The Better Player: Steady or Streaky?

First a little table-setting.  Maya and Tamika are fictional stand-ins.  Top players in the WNBA make 15-20 field-goal (two-point) attempts per game and sink 45-50% of those.  Maya’s performance is realistic, but whether Tamika’s streakiness is seen in actual players is a question for sports statisticians to answer.

Maya’s expected performance is easy to calculate.  Assuming she makes 20 attempts and sinks 50% of them, you may expect 10 field goals from her in a typical game, give or take.  The probability P(n) of Maya scoring exactly k field goals in n shots is given by

P(n) = \frac{n!}{k! (n-k)!} \;p^{k} q^{n-k}

where p is the probability of making any given shot and q is the probability of missing it.  [This is the well-known formula for the binomial probability distribution.  Exclamation points denote the factorial operation — they do not express my surprise.]  So the chance that Maya will score 10 +/- 1 field goals is about 50 percent:

Chance of 9 scores 0.160
Chance of 10 scores 0.176
Chance of 11 scores 0.160
Total 0.497

Predicting what to expect from Tamika is more complicated.  As I learned while studying this problem, her performance is an example of a Markov chain.  This is best explained by the diagram below.  Tamika starts the game in the Initial box.  After taking her first shot, she moves either to the Scored box (blue) or to the Missed box (violet).  The number next to each path shows the chance that she will follow that path when she shoots.

Every time Tamika shoots, she moves along a path.  Some paths return to the same box.  For instance, when Tamika is in the Scored box (i.e., she sank her last shot), she has an 80% chance (0.8) of circling back to the Scored box with her next shot.  Otherwise she moves over to the Missed box.  And so on.

No paths lead to the Initial box because, when taking a shot, Tamika only scores or misses. In my intro, I failed to specify how Tamika typically performs on her first shot.  For now, assume that Tamika starts the game cold as if she has just missed.  This implies that her chance of moving from Initial to Missed is 80% and from Initial to Scored is 20%.

The number of times Tamika visits the Scored box gives us the number of field goals you may expect her to score during the game.  But how do you calculate that?  Luckily, thanks to folks like David L. Deever, professor emeritus of Otterbein University in Ohio, there are such things as Markov chain calculators.  You enter the path information into a table, and the calculator returns the probability that a given box is occupied on the nth step.

Here are the results Dr. Deever’s calculator produced for Tamika.  The Scores column shows the expected number of times Tamika has scored after taking n shots:

The table shows that, after 20 shots, Tamika’s expected number of scores is 9.25, which is 0.75 less than the 10 scores you can expect from Maya.  Tamika never fully recovers from her cold start, and she will trail Maya by 0.75 scores (on average) forever.

So, if you had decided to start Steady Maya, your answer would be correct.

But perhaps you assumed Tamika has a 50/50 chance of scoring/missing on her first shot, after which the 80/20 rule would apply.  If that were the case, then Tamika would not fall behind Maya at all.  Each player would score 10 times in 20 shots, on average.  So if you guessed there would be no difference, your answer would also be correct.

• • • 

Tomorrow has turned into today, and your team is in the final minutes of its next game.  Since Maya had a slight edge over Tamika, you decided to start her today.  Unfortunately, your Lady Longhaulers have allowed too many turnovers, and they have fallen behind by 10 points.  You figure you will get five more possessions before the final buzzer.  To have any chance to win, your team will need to score on every one of those possessions.

You call a time-out.  Do you stay with Steady Maya or do you send in Streaky Tamika?

This gets interesting.  You need a player to sink five shots in a row.  The chance that Maya can do this is 0.5 (the probability of her sinking any one shot) to the fifth power, or 3.1%. The chance that Tamika can do it, coming in cold, is 0.2 (her first-shot success rate) times 0.8 (her repeat success rate) to the fourth power, or 8.2%.  Tamika is more than twice as likely to tie the score than Maya, though her chances are still slim.

So if your answer was to send in Streaky Tamika, you would be correct.  And this means that if your original answer was “it depends” then you would also be correct.  Now, all Tamika has to do is sink her first shot.  And the next.  And the next…

With that, your time-out is over.  May you enjoy the final minutes of your coaching career.

• • • 

David L. Deever, the author of journal articles as well as the Markov calculator that I used,  taught his last mathematics class at Otterbein University in 2003, ending a 37-year career.  His Facebook page (which has not been updated since 2013) reveals Dr. Deever to be a kind person, concerned citizen and a liberal in good standing.  I thank Dr. Deever for his contributions and I wish him good health.

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Pop songs usually have a hook, a lyrical or musical phrase that catches the listener’s ear and draws her into the song.  But some artists and producers don’t know when enough is enough and repeat the hook way way too many times.  Here is a partial list of those songs, including the number of times the hook appears* along with YouTube links.  (Use an ad-blocker when you listen.)  Feel free to add more nominees for the Too Many Hooks Award.

 Walk Away, Renee (4 times, feels like 8) by The Left Banke

√  Morning Train (6 times, feels like 12) by Sheena Easton

√  Werewolves of London (7) by Warren Zevon

  The Weight (“Take a load off Fanny”) (10) by The Band

√  We Are Never Ever Getting Back Together (10) by Taylor Swift

√  All I Wanna Do (10), A Change Would Do You Good (12) and practically every other song by Sheryl Crow

√  Still the One (14**) by Orleans

√  Can’t You See (16) by The Marshall Tucker Band

√  My Sharona (16) by The Knack

√  Blinded by the Light (19!) by Manfred Mann’s Earth Band

√  Taking Care 0f Business (26!) by Bachman Turner Overdrive

√  U Can’t Touch This (26) by MC Hammer

Some might say that “Hey Jude” by the Beatles, whose nah-nah-nah-nahs repeat 18 times, deserves to be included in this list, but those people would be wrong.  Eighteen wasn’t too many times then and isn’t too many times now.

_______

* I did the task of listening and counting so that you don’t have to.  You’re welcome.
** Orleans sings the words “still the one” a total of 22 times during the song but not always in the distinctive style of the hook.
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Fifteen years ago today, at around 5:30 PM, I locked my office door for the last time and walked away from my engineering career at Eastman Kodak.  Although I still think about some of my fellow workers and wonder how they are doing, I am not nearly so nostalgic about those days as I was when I wrote about them several years ago.  Simply put, I have been down those roads many times and there is no place left to go back there.

Yet October 30 remains a day of reflection for me, more so than my birthday.  These days, it is not my Kodak career that I’m apt to reflect upon but what has transpired since.

I floundered for some years after I left Kodak but not because work and career formed the bedrock of my life.  Rather it was because I hadn’t done much other than work and career, and (surprise!) it turned out that I wasn’t very good at the things I hadn’t practiced.

Before I left Kodak, I had pretty much followed the traditional American script: school, marriage, career, home, children.  I had lived in the same city and worked for the same company my entire adult life.  I mainly had to show up, be responsible, and work hard.  The last day I walked out the factory gate, the well-scripted part of my life was over.

Improvisation was never my strong suit and I knew it.  Nonetheless, I decided that I would rather wing it than go down with the ship, so to speak.  I knew that my future, if any, with Kodak would involve day-to-day firefighting on the factory floor, not a good match for my deliberate speed-of-thought.  I told myself I could start anew with the support of my wife, who was eager herself to leave the land of lake-effect snow.  So southward we bounded.

As someone who had thought entrepreneur was French for flamboyant doorman, I wound up making more mistakes and experiencing more failures, at least at the outset, than I had in my thirty-year career.  I aborted my foray into financial planning before it even began, when I realized that the middle-income clients who I hoped to serve simply didn’t exist in this area.  Then my poorly-marketed real estate photography stint crashed along with the rest of the economy in 2008.  Ironically, I wound up doing in desperation exactly what I did not want to do in my final days at Kodak: process troubleshooting for a local factory.  To further grind my face into the dust of my professionalism, management made me wear a uniform with my first name sewn onto the shirt.  Good morning, sir!  After I figure out what’s wrong with the machine this time, would you like me to check your oil?

I worked for that company, whose five-letter name remains a four-letter word to me, for as long as I could stand it.  I quit within weeks of looking at our finances and concluding that my wife and I could retire when we were ready.

I haven’t worked for money since then, so that must mean I am either retired or an artist.

Over time, I have lost touch with what work is about, why careers matter.  I can’t imagine having to get up every day at early-o’clock to shower, dress and drive to a desk — the idea seems almost barbaric now.  Although I keep inventing other things that matter (this blog, my art, the next household fix-it project), my approach to all of it is strictly Friday-casual.  If I even bother to change out of my sweatpants.

What should trouble me is that I have become increasingly sloppy with time management in my retirement.  While the young and healthy may get away with this, maybe people with vision and heart issues should not take so many hours of the day for granted.  That said, who wants to live his life as a frantic race against the clock?  There has got to be a balance.  I’m still trying to find it.

I spend a lot of my time writing this blog.  When I started it, a few months before I retired,  my posts were no more than long-form Facebook comments.  But over time, I developed a sense of what I wanted to say and how I wanted to say it, if not necessarily what readers find interesting to read.  (My reflections and ruminations can run long.)  Recently, my wife and marketing agent single-handedly increased my subscribers by 50%.  I appreciated her efforts (and the willingness of her friends to subscribe) but I am wary of the expectations.  After all, this isn’t meant to be work, even when it’s not all fun and games.

In any event, with this post I start my next 15 years of life after Kodak.  It’s been a full ride, with more adventures on the trail ahead.  So let’s giddy-up and stop looking back.

Tanque Verde Ranch, Arizona (October 2019)

 

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