Biased Coin

biasedcoin.py

import random

HEADS = 0
TAILS = 1

n = input("How many samples do you wish to compute?: ")
p = random.random()

print "probability of getting heads is:", p

correctGuesses = 0
wrongGuesses = 0

for i in range(0, n):

    choice = random.randint(HEADS, TAILS)

    coinFlip = random.random()

    # if we get a heads
    if coinFlip < p:
        # if we guessed heads
        if choice == HEADS:
            # then we guessed correctly
            correctGuesses = correctGuesses + 1
        else:
            # otherwise, we guessed wrong
            wrongGuesses = wrongGuesses + 1

    # otherwise if we got a tails
    else:
        # if we guessed tails
        if choice == TAILS:
            # then we guessed correctly
            correctGuesses = correctGuesses + 1
        else:
            # otherwise we got the guess wrong
            wrongGuesses = wrongGuesses + 1


percentageCorrect = float(correctGuesses) / n
print "correct guesses:", correctGuesses, "(" + str(percentageCorrect) + ")"
print "wrong guesses:", wrongGuesses, "(" + str(1 - percentageCorrect) + ")"