Je veux pouvoir analyser des données avec Python (partie 3)

(Partie 3)

1 jeu de jetons de pièces = lancer 3 fois

Ce n'était pas dans le livre, mais j'ai simplement changé "1 set 2 lancers" en "1 set 3 lancers" et changé le total de "4 lancers" à "6 lancers".

code

Il n'y a pas de commentaire. Le contenu est le même que les précédents (1) et (2).

from random import randint
from decimal import Decimal
from prettytable import PrettyTable
import numpy as np

def tossBiasedCoin():
    """ Returns 0 or 1 with 0 having 2/3 chance """
    return randint(0,2) % 2

# Make a 4x4 array
counts = [[0 for j in range(4)] for i in range(4)]

# Toss a coin many times to get counts
sampleCount = 500000
for num in range(sampleCount):    
    firstSet = [tossBiasedCoin(),tossBiasedCoin(),tossBiasedCoin()] # 0, 1, 2, 3
    secondSet = [tossBiasedCoin(),tossBiasedCoin(),tossBiasedCoin()]
    counts[sum(secondSet)][sum(firstSet)] += 1

# Conert all counts to perentage
TWOPLACES = Decimal(10) ** -2 
for i in range(4):
    for j in range(4):
        value = counts[i][j]        
        counts[i][j] = (100 * Decimal(counts[i][j])/Decimal(sampleCount)).quantize(TWOPLACES)
        print("Converted the value {} to percentage {}".format(value, counts[i][j]))

# Make summaries of number of heads.
keys = np.arange(7)
values = [counts[0][0], # 0
          counts[0][1]+counts[1][0], # 1
          counts[0][2]+counts[2][0]+counts[1][1],
          counts[0][3]+counts[1][2]+counts[2][1]+counts[3][0],
          counts[1][3]+counts[2][2]+counts[3][1],
          counts[2][3]+counts[3][2],
          counts[3][3]]
          
# Add row descriptions
counts[0].insert(0, '2nd set 0 head')
counts[1].insert(0, '2nd set 1 head')
counts[2].insert(0, '2nd set 2 heads')
counts[3].insert(0, '2nd set 3 heads')

# Create table with column descriptions, add rows, then show it.
table = PrettyTable(["", "1st set 0 head", "1st set 1 head", "1st set 2 heads", "1st set 3 heads"])
table.padding_width = 1
table.add_row(counts[0])
table.add_row(counts[1])
table.add_row(counts[2])
table.add_row(counts[3])
print table

# Draw a bar chart
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
rects = plt.bar(keys,
                 values, 
                 0.5,
                 alpha=0.4,
                 align="center", 
                 color='b')

plt.xlabel('Number of heads')
plt.ylabel('Probability (%)')
plt.title('Probabilities heads with a biased coin')
plt.xticks(keys, np.arange(7))

plt.tight_layout()
plt.show()

résultat

Cela ressemble plus à un écart type.

Le nombre de cartes qui peuvent être lancées à 6 est de "6 x 1/3", ce qui signifie qu'il est facile d'obtenir 2 cartes.

(Partie 4) se poursuit.