avg_time_viewed still does not make sense. The terminology page says “The average of minutes viewed by the user, calculated by quartile, per play.” Minutes viewed is “Total number of playback minutes played by the viewers, based on quartile milestones.”
This sounds like the number is the average (mean) of the average (mean) of the quartile reached for each play for each user.
The video is 10 minutes long.
User 1 watched 2 minutes of the video the first time, and 6 minutes the second time: (0+5)/2 = 2.5 minutes
User 2 watched 8 minutes: 7.5 minutes (3rd quartile)
Average time viewed = (2.5 + 7.5)/2 = 5 minutes
Is this correct?