I'm trying to learn Python through the lecture series at Quantopian and am having trouble understanding how to use scipy.stats.lognorm and the documentation.
This are the excerpts:
pdf(x, s, loc=0, scale=1)
ppf(q, s, loc=0, scale=1)
I've included the code found in the documentation: https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.lognorm.html
I would like to know how s = 0.954 is derived and what q stands for, and what does it mean when you change loc and scale? I know it shifts the functions but I don't really understand what it means, if somebody could explain this in a 'for dummies' way that would be great.
s = 0.954
mean, var, skew, kurt = lognorm.stats(s, moments='mvsk')
x = np.linspace(lognorm.ppf(0.01, s), lognorm.ppf(0.99, s), 100)
ax.plot(x, lognorm.pdf(x, s), 'r-', lw=5, alpha=0.6, label='lognorm pdf')