Sentence:  The assessor can then be asked to successively divide an interval into equally likely segments yielding the octiles (X<sub>.125</sub>, X<sub>.875</sub>), <WSD>hexadeciles</WSD> (X<sub>.0625</sub>, X<sub>.9375</sub>), etc., etc. 
Meaning of the word marked with <WSD> tags:  Any of the quantiles which divide an ordered sample population into sixteen equally numerous subsets; a subset thus obtained.