Help with statistical analysis
Posted: Sun Apr 06, 2014 3:09 pm
We had our Pinewood Derby last week and it went as well as it could have. Per my earlier posts, I inherited a totally unplanned derby with four weeks to go. I made the decision to bite the bullet and purchase a Best Track and Champ timer and it made for a successful event.
Our pack is not an ultra competitive pack as far as the Pinewood Derby goes; however, we do have a couple dads that are a bit out of control. We outsourced the event for a couple years, but last year I was not on the cub committee and they made the decision to use an old wooden track and try to determine the winner by having parents judge which car crossed first in each heat. One of the dads that is the source of trouble was very unhappy about the judging and that one of the lanes was obviously slower than the others. The individuals running the event did not know how to adjust or run heats to eliminate that and the event ended with this dad yelling and driving some of the den leaders to tears.
Fortunately we eliminated the potential for those problems with the track setup this year. This particular dad was overheard telling another parent that his son never actually touched the car they used this year. He said his son just wanted to win so he did not care that his dad built the car in its entirety. I would have disqualified the car had I heard that before the event ended. In addition to the sad fact that this individual seems to place some importance on his competing against 8-11 year old boys, the dad actually jumped up and fist pumped when I revealed the results with his car winning.
The format of our race was using the Perfect-N schedule and having each car race in each lane twice (six total races for each boy as we had a three lane track). I did a short intermission at the half-way point (each car had raced in each lane once) to let people lube their cars. The next time this particular car raced, it set a track record and was substantially lower than its previous three races. I am including the times below and asking is anyone thinks that the car was potentially altered to increase its speed. Adding weight would seem to be the only real option and in retrospect I should have done a post-race insepction and weighing of the top three cars. I would not have even thought this, but for the fact that the dad is so obsessed with winning.
Here are the times for the car in question for the six races:
Lane #1 3.25010
Lane #2 3.23020
Lane #3 3.23780
Lane #1 3.17870
Lane #2 3.24310
Lane #3 3.19470
I expect some pick up in speed if the car has not been "broken in", but I am sure this individual knows enough to run the wheels enough to break the car in before the race. The time in the following race is back to the same range the pre-intermission race times. The last time is considerably faster than the average also.
Our process was to have the boys remove the cars from the track and hold them until their next race at which point they place them at the starting line. Since we move pretty quickly, altering a car would be difficult during the racing since you might be called up to race at any point.
My quick analysis is that it is the fastest time is not quite two standard deviations from the mean, but it would fall in the 94th percentile of a normal standard distribution. The fact that it came right after the intermission is what makes me think something is amiss.
Ultimately, the event is done and I learned quite a bit that we will do differently next year. Curious as to how many people do a post-race inspection on cars. I am loathe to pull apart a car and potentially damage it, but a simple visual inspection and weighing does not seem to be too much.
Looking forward to any thoughts and want to say thanks for helping with my previous posts. Not sure we would have had the event we did without the information on this site.
Our pack is not an ultra competitive pack as far as the Pinewood Derby goes; however, we do have a couple dads that are a bit out of control. We outsourced the event for a couple years, but last year I was not on the cub committee and they made the decision to use an old wooden track and try to determine the winner by having parents judge which car crossed first in each heat. One of the dads that is the source of trouble was very unhappy about the judging and that one of the lanes was obviously slower than the others. The individuals running the event did not know how to adjust or run heats to eliminate that and the event ended with this dad yelling and driving some of the den leaders to tears.
Fortunately we eliminated the potential for those problems with the track setup this year. This particular dad was overheard telling another parent that his son never actually touched the car they used this year. He said his son just wanted to win so he did not care that his dad built the car in its entirety. I would have disqualified the car had I heard that before the event ended. In addition to the sad fact that this individual seems to place some importance on his competing against 8-11 year old boys, the dad actually jumped up and fist pumped when I revealed the results with his car winning.
The format of our race was using the Perfect-N schedule and having each car race in each lane twice (six total races for each boy as we had a three lane track). I did a short intermission at the half-way point (each car had raced in each lane once) to let people lube their cars. The next time this particular car raced, it set a track record and was substantially lower than its previous three races. I am including the times below and asking is anyone thinks that the car was potentially altered to increase its speed. Adding weight would seem to be the only real option and in retrospect I should have done a post-race insepction and weighing of the top three cars. I would not have even thought this, but for the fact that the dad is so obsessed with winning.
Here are the times for the car in question for the six races:
Lane #1 3.25010
Lane #2 3.23020
Lane #3 3.23780
Lane #1 3.17870
Lane #2 3.24310
Lane #3 3.19470
I expect some pick up in speed if the car has not been "broken in", but I am sure this individual knows enough to run the wheels enough to break the car in before the race. The time in the following race is back to the same range the pre-intermission race times. The last time is considerably faster than the average also.
Our process was to have the boys remove the cars from the track and hold them until their next race at which point they place them at the starting line. Since we move pretty quickly, altering a car would be difficult during the racing since you might be called up to race at any point.
My quick analysis is that it is the fastest time is not quite two standard deviations from the mean, but it would fall in the 94th percentile of a normal standard distribution. The fact that it came right after the intermission is what makes me think something is amiss.
Ultimately, the event is done and I learned quite a bit that we will do differently next year. Curious as to how many people do a post-race inspection on cars. I am loathe to pull apart a car and potentially damage it, but a simple visual inspection and weighing does not seem to be too much.
Looking forward to any thoughts and want to say thanks for helping with my previous posts. Not sure we would have had the event we did without the information on this site.