In my previous post, I noted the number of times volume on a specific day of the week exceeded the weekly average.  In this post, I construct the weekly average slightly differently.  I am going to calculate the weekly average by once again excluding the weekends, but by making the day-of-the-week the mid-point of the week.  For example, Monday's weekly average would be composed of the previous Thursday, the previous Friday, Monday, the next Tuesday and the next Wednesday.  Tuesday's average would be the previous Friday, the previous Monday, Tuesday, and the following Wednesday and Thursday.  This was an attempt to put the days of the week in the middle of a spam outbreak.  Again, excluding weekends skews the data some but one day I'll go back and account for it.

The following is the number of times each day of the week exceeds its mid-point average:

Monday Tuesday Wednesday Thursday Friday
Above avg      20     28       33        20      19
Below avg      28     20       15        28      29

The results for the first three days of the week are nearly identical from before, but Thursdays and Fridays experience a major change.  Thursdays experience 6 fewer days above average and Fridays experience 4 fewer days.  Going by this data, Tuesdays and Wednesdays account for far more spamming days than the other weekdays, in fact, more than the rest put together.  If you're an anti-spam company, it might make more sense to make sure Tuesdays and Wednesdays are appropriately scheduled.

The following is the daily volume as a percentage of the weekly average:

Monday  Tuesday  Wednesday  Thursday  Friday
Average - all   98.84%  100.48%   101.98%    99.70%   98.70%
Above average  103.70%  103.75%   104.66%   103.69%  103.30%
Below average   95.36%   95.90%    96.10%    96.85%   95.69%

The results on this table are only slightly different than the above table; overall, Friday experiences slightly lower volumes than before, demonstrating that where you take your measurements can make a difference.  In fact, Monday pulls ahead of Friday in terms of daily volume as a percentage of the mid-week average.  The rest of the numbers are relatively unchanged, though there is a bit of a counter-surge trend - that is, the swing above or below average for the days are marginally smaller.  Wednesday, however, still remains the spammiest day of the week.