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## Calculating likelihood of X% of entrants advancing in an NFL Survivor Pool

or: Yes, Week 2 of the 2015 NFL season probably was the toughest week for a survivor pool, ever.

Week 2 of the 2015 NFL season was rife with upsets, with 9 of 16 underdogs winning their games.  This wreaked havoc on survivor pools (aka eliminator pools), where the object is to pick a single team to win each week.  The six most popular teams (according to Yahoo! sports) all lost:

(image from Yahoo! Sports, backed up here as it looks like the URL will not be stable into next year)

About 4.6% of Yahoo! participants survived the week (I looked only at the top 11 picks due to data availability, see the GitHub file below for more details).  This week left me wondering: was this the greatest % of survivor pool entrants to lose in a single week, ever?  And what were the odds of this happening going into this week?

I wrote some quick code to run a million simulations of the 2nd week of the 2015 NFL season (available here on GitHub).

Results

Given the projected win probabilities (based on Vegas odds) and the pick distributions, only 684 of the 1,000,000 simulations yielded a win rate below the 4.6% actual figure.  Thus the likelihood that only 4.6% of entrants would make it through the week was 0.0684%, less than a tenth of one percent.  Or to put it another way, this event had a 1-in-1,462 chance of occurring.

Here are the results of the simulation:

1. Blue line: median expected result, 80.6% winners
2. Yellow line: 1st percentile result, 13.8% winners (to give you a sense of how rare a result this week was)
3. Red line: actual result, 4.6% winners

So was it the greatest week for survivor pool carnage ever?  Probably.  You might never see a week like it again in your lifetime.

P.S. This distribution is pretty cool, with the sudden drop off and gradual climb starting at x = 0.50.  This is caused by 50% of the pool picking the Saints, the most likely team to win.  I wouldn’t say this is a bimodal distribution, exactly – is there a term for this?

Categories

## Smoked Porter 2015

Over the 4th of July, I smoked about 3 lbs of Pils malt on an old potbelly stove.  It smoked with mesquite chips for a few hours in two batches, then was left to condition for ~7 weeks in an open paper grocery bag.

I first brewed a smoked porter with home-smoked malt in 2011.  I used alder chips then, in an homage to Alaskan Brewing Co.’s Smoked Porter.  It turned out well and the bottle I opened yesterday as I brewed the 2015 version has aged nicely.  The biggest flaw is that the smoke flavor is too phenolic.  I tried to avoid chlorinated water throughout the process but may not have succeeded.

I brewed this year’s smoked porter on the same potbelly stove I used to smoke the malt.  I’ve already written about the process of brewing on the potbelly stove, so I’ll stick to the recipe and batch notes here.

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## Homebrewing on a Potbelly Stove

My in-laws have an old potbelly stove sitting around.  Some research indicates it was made around 1900.  I smoked about 3 lbs of Pils malt on this stove on the 4th of July, and decided I’d see if it could crank out enough heat to brew a 5 gallon batch of beer.

It heated about 4.5 gallons of mash water fairly well, heating it 86.7 degrees in an hour.  The slope leveled off a little as it reached strike temperature:

This performance of 390 degree-gallons per hour (when heating water starting at room temperature) is not too much worse than this same pot when I’m heating with a 1500W, 120V electric element – that setup yields about 480 degree-gallons per hour.

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## I have a blog

Why a blog?  I have two main purposes in mind:

1. Opinions & ideas that are too long for my Twitter my Mastodon.  I’ll probably tweet toot links to these posts.
2. Knowledge management: I often make things after reading on the web about how to make them.  Sometimes I think, “the internet was wrong” or “I could explain it better than that.”  Now I have a space to see whether I can make some small contributions to human knowledge that others might stumble upon and benefit from.  I benefit tremendously from internet knowledge so I ought to give back what I can.
1. I will also benefit from my own notes on past projects.  In particular, I use Brewtoad to design homebrew recipes, but lack a good system for storing notes on the process & results.  I like how the Mad Fermentationist logs his brews on a WordPress blog.

Given that this may be a jumble of posts on DIY, beer, electoral politics, data analysis, etc. I expect that very few people will read through the blog continuously or follow it.  But if a few of the right readers find each post via other means, that’ll do.  And if no one reads it, at least I have a place to take notes.