Outlier - Textbook example

I have a short post today, gentle readers.  It appears that The Joy of Teaching... Algebra had a noticeable spike in pageviews on 2 Aug 2011 (last Tuesday).  And if there's one thing I love, it is real data.  The following is a line graph of my daily views over the last month.

Click to enlarge

There are cases where an experienced data analyst can spot an outlying data point without the use of quality control charts.  I am a journeyman data analyst, and in my professional opinion, the 2 Aug number of 68 pageviews is a clear outlier.  By comparison, the second largest point is 20 on 11 July.  Since I wrote an entry on 11 July, it is entirely possible that many of these 20 views are my own. I've since turned on the option to avoid counting my own views, so it is unlikely that these views are mine.  At least, I hope they aren't, since I find narcissism rather unbecoming.

The significance of this statistical anomaly is a mystery to me at this point. Consequently, I would love to know if any of my gentle readers can shed some light on this occurrence.  If it might help, the views all appear to have occurred over a two hour time frame beginning approximately at 9:00 pm Central on Tuesday 2 Aug.

Upcoming items

I've not forgotten my promises to report on my linear algebra classroom blogging and my qualitative comparison of letter grades.  These are ongoing items, and I will be prepared to write about them by the time classes start on 22 Aug.