"""This file contains code for use with "Think Bayes",
by Allen B. Downey, available from greenteapress.com
Copyright 2012 Allen B. Downey
License: GNU GPLv3 http://www.gnu.org/licenses/gpl.html
"""
from thinkbayes import Suite
class M_and_M(Suite):
"""Map from hypothesis (A or B) to probability."""
mix94 = dict(brown=30,
yellow=20,
red=20,
green=10,
orange=10,
tan=10,
blue=0)
mix96 = dict(blue=24,
green=20,
orange=16,
yellow=14,
red=13,
brown=13,
tan=0)
hypoA = dict(bag1=mix94, bag2=mix96)
hypoB = dict(bag1=mix96, bag2=mix94)
hypotheses = dict(A=hypoA, B=hypoB)
def Likelihood(self, data, hypo):
"""Computes the likelihood of the data under the hypothesis.
hypo: string hypothesis (A or B)
data: tuple of string bag, string color
"""
bag, color = data
mix = self.hypotheses[hypo][bag]
like = mix[color]
return like
def main():
suite = M_and_M('AB')
suite.Update(('bag1', 'yellow'))
suite.Update(('bag2', 'green'))
suite.Print()
if __name__ == '__main__':
main()
