Continuous distributions are modeled by the probability density functions (pdf). The probability for a certain interval is determined by integration of the probability density function. The NumPy random module has a number of functions that represent continuous distributions—beta, chisquare, exponential, f, gamma, gumbel, laplace, lognormal, logistic, multivariate_normal, noncentral_chisquare, noncentral_f, normal, and others.