Returns a new NormalDist object where mu represents the arithmetic mean and sigma represents the standard deviation.
class statistics.NormalDist(mu=0.0, sigma=1.0)>>> temperature_february = NormalDist(5, 2.5) Celsius
>>> temperature_february * (9/5) + 32 Fahrenheit
NormalDist(mu=41.0, sigma=4.5)>>> birth_weights = NormalDist.from_samples([2.5, 3.1, 2.1, 2.4, 2.7, 3.5])
>>> drug_effects = NormalDist(0.4, 0.15)
>>> combined = birth_weights + drug_effects
>>> round(combined.mean, 1)
3.1
>>> round(combined.stdev, 1)
0.5