December 5, 2005
Wired, NASDAQ, and the Christmas Question
At least two recent blog entries suggest a possible connection between the page count of Wired magazine and the NASDAQ stock index. One commenter suggested that this month's large page count was due to what he termed the "'Wired is a christmas whore' phenomenon."
So two questions come up.
- Does the page count vary by season?
- Is the proposed relationship between the NASDAQ and the magazine's page count affected by seasonality?
First variation by season. December does have an empirically higher mean page count than all other months. Taking a sample of the last 10-11 years as representative of all years, several months are significantly different from December. The plot below shows how much higher December is than each month on average with 95% Tukey confidence intervals.
I think the second question is more interesting, but the resulting analysis is one step removed from the data. It examines the residuals from a linear regression of the NASDAQ on the page count. See the scatter plot with regression line below.
I've indicated which data points are from November and December. 8/10 Novembers and 9/11 Decembers have page counts that would suggest higher NASDAQ's than actually occurred. That is, they have negative residuals.
Do November and December have residuals that are significantly lower than zero? If we compare the mean residual to zero for each month, November's mean is significantly different from zero (p=.046) and December's is nearly significantly different (p=.052). Each month's mean with corresponding 95% confidence interval is shown below.
Looking back at the scatter plot, my conclusion is that high page counts (> 250) are all either attributable to a surging tech market or the approach of christmas (Nov/Dec).
Posted by roge0285 at December 5, 2005 9:53 AM | Statistical Analysis