How are the 7-day Departure Time Averages calculated? Is the time based on previous full week? I’m assuming I have been out of school long enough that my math is rusty because I keep getting a different time than your website when doing the math myself? And by the way, I know this is a complete waste of time on my part but it’s bugging me that I can’t figure it out.
For instance, take DAL871:http://flightaware.com/live/flight/DAL871/history/20111213/1210Z/KJAN/KATL
As of today (12/13/2011) DAL871 has a 7-day departure Average of 6:20am. I tried calculating that avg two ways: (1) including today and (2) skipping today and beginning 12/12. My calculations come out to 6:17am (rounded up) for today and 6:15am (rounded up) as of yesterday.
Here is my math including today (all minutes were converted to decimal).
0.316666667 (Dec 13)
0.05 (Dec 12)
0.083333333 (Dec 11)
0.466666667 (Dec 10)
0.133333333 (Dec 9)
0.566666667 (Dec 8 )
0.35 (Dec 7)
1.966666667 / 7 = .281 * 60 = 16.85714 or 6:17am
Explanation of sum from above:
(SUM numbers from Dec 13th to 7th) divided by 7 days = Answer multiplied by 60 (convert back to minutes) = average departure time in minutes