April 27, 2010

Boobday statistics

Just a quick exercise with Matlab and the USGS earthquake data to check whether the boobquake experiment did produce extra earthquakes.

The answer is no.

Here are the earthquakes in the period 2010/04/20 09:57:38 to 2010/04/27 09:31:10, plotted by latitude and longitude. Boobday quakes are red (to be on the sure side I include everything on the 26th and 7 hours later, to take American local time into account).

There are some dense clusters in Alaska, southern California and the Caribbean. While I can believe immodest clothing is common in the later two, Alaska is not widely known for scantily clothed women. The biggest earthquakes were in the south-western Ryuku Islands, Indonesia, Chile and Tonga. Again, I can imagine some immodesty on tropical islands. But note that the boobday quakes are not centred around locations that are likely to have many English-speaking sceptics.

Plotting magnitude versus time gives us this plot:

There is no clear tendency for more or more intense earthquakes during boobday. Plotting the mean magnitude for the two kinds of quakes gives us this bar diagram:

Running a two-sided Wilcoxon rank sum test on the data gives p=0.7355, so it is not possible to reject the null hypothesis that there is no difference at all. So immodesty does not increase the magnitude noticeably.

Comparing the number of earthquakes over time also gives a very similar result. Here I have compared boobday with an equally long time interval starting on the 24th:

No noticeable difference. No difference at all, actually - both periods had 54 quakes. Maybe divine anger expresses itself as an increase in micro-quakes below 2.5 on the Richter scale, but that seems to be a pretty weak claim.

Hojatoleslam Kazem Sedighi's bold hypothesis that immodest female clothing increases earthquakes appears to be refuted, unless he can claim the increase in immodesty caused by the boobquake experiment was insignificant (which no doubt he will do in his follow-up paper about why Facebook sceptics cause earthquakes).

But if the experiment was too small to produce measurable divine anger, then he should perhaps consider the issue whether the ambient immodesty in different locations explains their earthquake frequency. There were after all some big quakes or quake clusters near sunny islands. However, given the well known earthquake density map he will need some pretty complex explanations.What about the dense cluster across Iran? Or the absence of quakes in Brazil? Are the mid-oceanic earthquakes due to mermaids?

Posted by Anders3 at April 27, 2010 01:12 PM