The following bug has been logged online:

Bug reference: 2467
Logged by: Rae Stiening
Email address: stiening@stiening.com
PostgreSQL version: 8.1.4
Operating system: Linux
Description: Documentation
Details:

Table 9-3. Mathematical Functions

Description of the "width_bucket(...)"

"return the bucket to which operand would be assigned in an equidepth
histogram with count buckets, an upper bound of b1, and a lower bound of
b2"

I believe that the lower bound is b1 and upper b2.

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