I want to plot a gamma distribution with alpha = 29 (the scale) and beta = 3 (the size). In other words, I want to plot the pdf for Gamma(29,3). How do I do this if according to the documentation, the python gamma function only has parameters a and x and the size parameter doesn't exist?
I thought loc was beta, but I think it's actually offset, so the code below is wrong...
import numpy as np
import scipy.stats as stats
from matplotlib import pyplot as plt
x = np.linspace (0, 100, 200)
y1 = stats.gamma.pdf(x, a=29, loc=3) #a is alpha, loc is beta???
plt.plot(x, y1, "y-", label=(r'$\alpha=29, \beta=3$'))
plt.ylim([0,0.08])
plt.xlim([0,150])
plt.show()
According to the documentation, you want to use the scale parameter (theta), but since you are defining beta, which is the inverse of theta, then you pass scale with the value of 1/beta, which in your example would be 1/3 or 0.33333.
Therefore, try:
y1 = stats.gamma.pdf(x, a=29, scale=0.33333)