Friday, November 8, 2013

Predicting Your UpChuck Time with Your StumpJump Time

Over on Upchuck's Facebook page, the organizers commented that a good rule of thumb for average runners is to add 30-40 minutes to their StumpJump time. So, using the finishing times of both races (thanks again to UltraSignup) I created a very simple prediction model with a table and plot below. I found all runners who have finished both races, averaged their times, and ran them through an OLS model. If you want to see what a real statistician can do with this data, check out Dr. Chris Fonnesbeck's analysis for something a little more stringent (much thanks to him as he's mentoring me). I am showing you the results of my prediction model below as it's a little less intimidating, and it bears very nearly the same results as Fonnesbeck's.

I wish I had more time to spend on this, but I've run out and I wanted to get it out there before the race tomorrow. Head over to the Facebook page if you want to add to the discussion.

Prediction Table

So the table below has two recommendations. I call them DirectorRecommendation and ModelRecommendation. I've simplified the Director's recommendation to add 40 minutes as it gives you the more conservative estimate rather than the 30-40 minute range. So for example, if you've run the StumpJump in a time of 4 hours, the Director expects you to finish in 4:40 while the Model expects you to finish in 5:00. Interesting, a difference of 20 minutes. As you continue reading down the table, you'll see that for a StumpJump time of 5:30, both the Director and the Model agree that you will finish in about 6:10, no difference. Reading further if you finished StumpJump in 8:00, the Director expects 8:40 while the model expects 8:05.

StumpJumpTime DirectorRecommendation ModelRecommendation
04:00:00 04:40:00 05:00:46
04:30:00 05:10:00 05:23:51
05:00:00 05:40:00 05:46:57.1
05:30:00 06:10:00 06:10:02.3
06:00:00 06:40:00 06:33:07.5
06:30:00 07:10:00 06:56:12.6
07:00:00 07:40:00 07:19:17.8
07:30:00 08:10:00 07:42:22.9
08:00:00 08:40:00 08:05:27.11
08:30:00 09:10:00 08:28:32.12
09:00:00 09:40:00 08:51:37.14


The DirectorRecommendation is the red line, while the ModelRecommendation is the blue line. Start by finding your StumpJump time on the X axis with your computer mouse, scroll up to either one of the lines, then scroll to the left to get your predicted UpChuck Time.

plot of chunk unnamed-chunk-3

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