13.3 Histograms

A histogram is a form of bar chart for displaying statistical data. In Figure 5.12 in section 5.7.2, I showed a plot of one million random numbers in a normal distribution with mean μ = 1.0 and standard deviation σ = 0.2. This code creates a histogram with the same characteristics:

import matplotlib.pyplot as plt
import numpy as np

plt.clf()

np.random.seed(23)

# generate the random numbers in a normal distribution
mu = 1.0
sigma = 0.2
random_numbers = np.random.normal(mu, sigma, 1000000)

# set the number of bins in which to divide up the random numbers
bin_size = 100

# draw the histogram
the_plot = plt.hist(random_numbers, bins=bin_size)

<Figure size 432x288 with 1 Axes>

plt.show()

The bins argument determines how many bars are in the histogram.

Exercise 13.13

Does decreasing bin_size make the histogram smoother or blockier?

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