Mathematics.
certain invent in a time interval. lamda = 20 x = np.arange(0,40,1,dtype=int) y = [] for x_ in x: x_ = int(x_) y.append(lamda**x_*np.exp(-lamda)/factorial(x_)) plt.bar(x,y) plt.show() A poisson distribution with λ = 20 looks like : Poisson Distribution ( λ = 20 ) 2. Continuous Distributions A