A timing sample
Suppose repeated time measurements have a mean of 0.6 and a maximum of 1.3. The maximum lies 0.7 above the mean; symmetry would require a measurement of −0.1, which is impossible for elapsed time. The sample is lopsided. section 15.3
A raw moment collects powers of observations measured from zero. The zeroth counts observations, the first sums their values, and the second sums their squares. Dividing such a sum by the observation count gives its average power. section 15.3
TAKEAWAY: Raw moments are building blocks for statistics of repeated measurements, including quantities used to describe their spread and asymmetry. They are not themselves measurements relative to the sample mean. section 15.3
