1. A deterministic component model determining apparatus that determines a type of a deterministic component included in a probability density function supplied thereto, comprising: a standard deviation calculating section that calculates a standard deviation of the probability density function; a spectrum calculating section that calculates a spectrum of the probability density function; a null frequency detecting section that detects a null frequency of the spectrum; a theoretical value calculating section that calculates a theoretical value of a spectrum for each of a plurality of predetermined types of deterministic components, based on the null frequency detected by the null frequency detecting section; a measured value calculating section that calculates a measured value of the spectrum for the deterministic component included in the probability density function, based on the standard deviation calculated by the standard deviation calculating section and the spectrum calculated by the spectrum calculating section; and a model determining section that determines the type of the deterministic component included in the probability density function to be the type of deterministic component corresponding to a theoretical value closest to the measured value calculated by the measured value calculating section, from among the theoretical values calculated by the theoretical value calculating section for the plurality of types of deterministic components.