Using Math To Determine if You Are :)
Some of you may be old enough to remember the rage of biorhythms. Now classified as pseudoscience, biorhythmns were the use of mathematical cycles (e.g. sine and cosine curves) to predict emotional aspects of a person's life. I remember introducing students to biorhythms as an application of trig functions.
Now, the idea seems to have resurfaced. Cornell University researchers have analyzed 400 twitter messages of 2.4 million people in 84 countries. They used textual analysis to determine mood categories (e.g. "awesome" for positive mood, "annoy" for negative mood), as well as the use of emoticons (e.g. ":)")
The results in the prestigious journal Science support their claim to have "discovered that the emotional tone of people’s messages followed a similar pattern not only through the day but also through the week and the changing seasons."
Three patterns were evident:
 Positive posts occur in the morning (69 am), fall gradually during the day until 4 pm, then rise slightly after dinner

 Positive and negative messages were equally likely across seasons (i.e. no evidence of winter blues)
Now, the application process can begin again. Students can be introduced to biorhythmiclike curves as a more sophisticated application of trig functions (e.g. Fourier transforms) and statistics. Try it...it could be a fun exploration.
Source: B. Carey's "Study of Twitter Messages Tracks When We Are :)" NYT, 9/30/2011
