Assuming you're getting norm from scipy.stats, you probably just need to sort your list:
import numpy as np
import scipy.stats as stats
import matplotlib.pyplot as plt
h = [186, 176, 158, 180, 186, 168, 168, 164, 178, 170, 189, 195, 172,
187, 180, 186, 185, 168, 179, 178, 183, 179, 170, 175, 186, 159,
161, 178, 175, 185, 175, 162, 173, 172, 177, 175, 172, 177, 180]
h.sort()
hmean = np.mean(h)
hstd = np.std(h)
pdf = stats.norm.pdf(h, hmean, hstd)
plt.plot(h, pdf) # including h here is crucial
And so I get:
