Originally posted by

**JeffHamm**View PostThe data for rigor follows what's called a "log normal distribution". Basically, if you take the natural log of the hours, then look at the distribution it will be normal (typical bell shaped distribution). Log normal distributions are skewed in terms of the "hours", but are normally distributed in terms of the "ln(hours)".

I've plotted the data and the model function:

if you want to play with it, and have excel, if you paste the following into Cell B1, then you can enter a number of hours in Cell A1 and the formula will return the probability of reaching full rigor by that time.

=NORMSDIST((LN(A1-0.648)-1.38)/0.527)

Also, the 95% confidence interval is that a body will reach full rigor between 2.05 and 11.8 hours, with half reaching full rigor after 4.625 hours.

now, I don't know under what conditions this data was collected (it's certainly not going to be ones similar to how Annie Chapman was found, but far more likely going to be people who died in care, so at room temperatures, not disemboweled, etc. Be that as it may, I thought some may be interested.

- Jeff

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