import matplotlib.pyplot as plt
import numpy as np
import scipy.stats as st
import arviz as az
plt.style.use('arviz-darkgrid')
x = np.linspace(0, 3, 100)
mus = [0., 0., 0.]
sigmas = [.25, .5, 1.]
for mu, sigma in zip(mus, sigmas):
    pdf = st.lognorm.pdf(x, sigma, scale=np.exp(mu))
    plt.plot(x, pdf, label=r'$\mu$ = {}, $\sigma$ = {}'.format(mu, sigma))
plt.xlabel('x', fontsize=12)
plt.ylabel('f(x)', fontsize=12)
plt.legend(loc=1)
plt.show()