Fig. 2

Probability distributions used over the derived risk intervals for serious adverse effects. The uniform distribution puts equal belief over the entire interval from zero to the upper limit, and so has an expected value of half the upper limit. The truncated exponential distributions, on the other hand, put increasingly more belief on low risks. Their expected values are 0.19, 0.020 and 0.0020 times the upper limit, respectively. Note that to benefit the clarity of the display, the graphs for the two left-most exponential distributions have been truncated: in reality they extend much higher for risks close to zero