Previous research [C. E. Gelfer, unpublished doctoral dissertation, City University of New York Graduate Center (1987)] demonstrated stability in fundamental frequency (F0) declination across uttererance of various lengths that appeared to be derived from a stable underlying subglottal pressure (Ps). Moreover, this stability was maintained even when airflow requirements were varied in response to the varying phonetic composition of utterances. However, although a preliminary mathematical analysis suggested that both the Ps and F0 could be characterized as second order linear systems, no formal testing of these curves was performed. In this study we compare these data employing the following statistical procedure. First, we hypothesize that the data from both sets can be modeled by a curve of the form y=axbecx, with unknown parameters a, b, and c which are computed. We then consider a multivariate confidence interval for the vector (a,b,c) of fitted parameters, as well as the difference of the vectors for two such models. The comparison is made through distributional estimates obtained via Monte Carlo simulation.