Each measurement relates electrical voltage in the chewing muscle, M. masseter, with the corresponding force exercised by the muscle and measured as pressure on a probe on which subjects bite during the experiment. A sensor attached to the probe measures force exercised. Subjects were asked to adjust their biting pressure in such a way as to achieve a fixed prescribed pressure which was varied.
Voltage is the dependent variable and force the independent variable.
The data were recorded in the dental clinic of the University of Marburg, Germany, around 1986. Earlier analyses involved issues of local bandwidth choice, of estimating a variance function, and of quasi-likelihood modelling. Nonparametric regression analysis for longitudinal data. Lecture Notes in Statistics vol. 46, Springer, pp.