Sunday, 8 March 2009

The human footprint

Some time ago I saw the British documentary The Human Footprint. This documentary shows u how much milk an average British person drinks, how many chickens they consume, the total length of fingernails such a person grows during their lifespan and how often they have sex.
About this last topic an interesting remark was made: researchers don't just ask “how often do you have sex?” to a large group of individuals, that would give very unreliable results. To estimate the average frequency of sexual activity in British adults, the researchers asked: “how long ago did you last have sex?”
How does one calculate the average frequency of sexual activity on the basis of data on time since last activity? For example, if a man answers “the day before yesterday”, we know he doesn’t have sex every day. But we do not know whether he has sex about every two days, once a week, or once a month. It may even be a once-a-lifetime experience for the man.
Because of this asymmetry, one cannot simply assume that the given length of time is half way the average inter-intercourse period. If I want to learn how to calculate average frequency of sexual activity (the average occurrence of volcanic eruptions, or other semi-periodic events), I need to find out about waiting time theory. It is a topic I have not had to deal with since 1994; luckily I still have most of the university books I used.

No comments:

Post a Comment