Just How Fast is Jenny Cook?

And you thought I had gone quietly into that statistical night! Ha! No oceanswim season would be complete without an in-depth analysis of just who is faster than whom. I know, I know, I tried it last year and while the analysis was riveting, the outcome at Catalina was known with probability one by anyone, with or without freshman calculus on his/her transcript. But why give in to sanity? Especially when I know the MSR faithful readers live for this stuff. Numbers, numbers, numbers, they always say to me at practice - give me the stats! So earlier this year, an analysis of Evanswich mean distance was presented as a simple respite from the weekly droning on about this swim and that swim, a statistical appetizer if you will. Now we get some real (some might say geeky but I know none of you would) analysis about a certain swimmer who has struck fear into the macho hearts (and elsewhere) of members of a certain gender. That swimmer is our own Jenny Cook, an Oceanswimmer of the Year! Here's a great picture of Jenny with SCAQer Peter Egan. How to gauge this woman's constant improvement? At first glance, a paired analysis seemed right, and what better pairing any fledgling statistician knows than a comparison within the same experimental unit across time. However, the vagrancies of the weather, conditions, and yes the race organizers (see that Evanswich mean distance again) made such internal comparison impossible. So the search for a true constant, an origin, indeed a guiding light that would also ebb and flow with the shivering scale, waves and all else, was undertaken. First, I considered myself. I am slow, that's a constant, but definitely getting slower year by year, indeed day by day, if not minute by minute. How to adjust for such trend? It seemed way too complicated, and let's face it, way too depressing. So I thought a little harder, here at the old thinktank. What other swimmer immediately came to mind? Why our oceanswimming buddy Alex Kostich, himself an Oceanswimmer of the Year, and frankly a very good sport whenever he is part of a famous MSR analysis (thanks Alex!). He is quite simply fast, a constant if there ever was one.

As usual with statistical exercises, and being a frequentist, I first gathered data. For each of our two swimmers, I observed those swims in both 2000 and 2001 that both had swum. For each common swim, I calculated the ratio of Cook time to Kostich time. Thus, if fast Jenny takes 25 minutes to do a swim, and faster Alex takes 20 minutes, the ratio is 1.25 indicating that Alex swam 1.25 times as fast as Jenny at that particular competition. On the attached graph, we see the 2000 swim ratios as four green diamonds and the 2001 swim ratios as ten blue squares arrayed across the summer season as our two brave swimmers battled the elements in their quests for View Oceanrace Series glory. The green line indicates the average 2000 ratio and the blue line indicates the average 2001 ratio. The latter is smaller than the former, indicating that even controlling for any improvement Kostich has made from 2000 to 2001, and let's give him credit (the guy works incredibly hard, though it's hard to see how one could become much faster if one is the fastest, isn't it? he's approaching an asymptote as we mathy-types say), Jenny is definitely getting faster and faster. For the two races, Corona and Hawaii, that both swimmers did both years, you can see the ratios dropping as shown by the downward red arrows. Down the bottom of the graph, the ratio of one is shown, or equality with Kostich, a line rapidly being approached by our own Dawn Heckman but that's another story and perhaps just too close to home for our macho readers. Suffice to say that Jenny is a fast swimmer getting faster, and Alex, well he's not so bad either.

I readily conclude from this analysis that in roughly the year 2035, when Lara Evans is our fearless leader, Jenny Cook will be seen running up the beach just as Alex hits the wave line (meanwhile I'll have drowned somewhere just beyond the start line). Until then, stay tuned for Jenny's improvement in next year's 2002 Morton Salt Report! Congrats to Jenny and all our brave oceanswimmers this past 2001 Oceanswim season!