[Bruce Abbott (2018.08.27.1545 EDT)]

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[Rick Marken 2018-08-26_15:19:21]

RM: So Moaz et al found exactly what we found: When affine velocity is left out of the regression analysis that is used to determine whether or not a movement conforms to the power law, the power coefficient relating curvature to velocity that is found by this omitted variable regression will deviate from the power law value – the mathematically “true” value of -1/3, 1/3 or 2/3, depending on how velocity and curvature are measured – by an amount proportional to the covariance between curvature and affine velocity (per equation (6) in Moaz et al and equation (12) in Marken and Shaffer (2017).

â€œThere are three kinds of lies: Lies, damned lies, and statistics!â€? – Mark Twain in a quote attributed to British Primee Minister Benjamin Disraeli.

Bruce