If on-off periods are defined for a regression variable using the "Epoch" section with zeros as replacement values for inactive/off periods, then those zeros incorrectly enter the calculation of the sample means. As a consequence, the sample means are biased towards zero and the centred regression variable does not average to zero over the active/on periods.
If on-off periods are defined for a regression variable using the "Epoch" section with zeros as replacement values for inactive/off periods, then those zeros incorrectly enter the calculation of the sample means. As a consequence, the sample means are biased towards zero and the centred regression variable does not average to zero over the active/on periods.