pm21-dragon/exercises/release/exercise-12/3__Monty_Hall_problem.ipynb

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2025-01-17 02:35:03 -05:00
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"# The Monty Hall problem (Deutsch: Ziegenproblem)\n",
"\n",
"Read about it [on Wikipedia](https://en.wikipedia.org/wiki/Monty_Hall_problem) or [in German as the Ziegenproblem](https://de.wikipedia.org/wiki/Ziegenproblem) and come back. I'll wait.\n",
"\n",
"In this notebook, you will write a program to simulated the Monty Hall problem.\n",
"\n",
"We are going to make extensive use of the function `random.randint(a, b)`. From its docstring, it returns a `random integer in range [a, b], including both end points.`"
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"import random"
]
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"for i in range(10):\n",
" print(random.randint(0,2))"
]
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"### Q1\n",
"\n",
"For your first task, create a function called `sample_not` which takes two positional arguments (call them `not1` and `not2`) and will return a random integer between 0 and 2 (endpoints included) but which is not either of the arguments. The positional arguments will always be integers between 0 and 2 (inclusive)."
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"# YOUR CODE HERE\n",
"raise NotImplementedError()"
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"# This is a test of the above, do not change this code.\n",
"assert sample_not(0,1)==2\n",
"assert sample_not(0,2)==1\n",
"assert sample_not(1,0)==2\n",
"assert sample_not(1,2)==0\n",
"assert sample_not(2,0)==1\n",
"assert sample_not(2,1)==0\n",
"assert sample_not(0,1)==2\n",
"assert sample_not(0,0) in (1,2)\n",
"assert sample_not(1,1) in (0,2)\n",
"assert sample_not(2,2) in (0,1)"
]
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"### Q2\n",
"\n",
"For your next task, consider the following code:\n",
"\n",
"```python\n",
"\n",
"# generate what is behind the doors\n",
"doors = ['goat', 'goat', 'goat']\n",
"car_door = random.randint(0,2)\n",
"doors[car_door] = 'car'\n",
"\n",
"# Now, the guest makes a first guess.\n",
"guess1 = random.randint(0,2)\n",
"\n",
"# Now, the host opens a door, which is not the guess or the car.\n",
"host_open_door = sample_not(guess1,car_door)\n",
"\n",
"# Based on the variable `do_switch` (which is not set here), the guess will either make a new choice or stay with the original guess.\n",
"if do_switch:\n",
" guess2 = sample_not(guess1,host_open_door)\n",
" final_guess = guess2\n",
"else:\n",
" final_guess = guess1\n",
"\n",
"# Finally, determine what was behind the door for the final guess.\n",
"result = doors[final_guess]\n",
"```\n",
"\n",
"Put this code in a function called `run_game` which takes a single argument, `do_switch`, and returns a boolean, indicating a win with `True` or a loss with `False`."
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"# YOUR CODE HERE\n",
"raise NotImplementedError()"
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"# This is a test of the above, do not change this code.\n",
"count = 300\n",
"for do_switch in (True, False):\n",
" wins = 0\n",
" for i in range(count):\n",
" this_run_win = run_game(do_switch)\n",
" assert(type(this_run_win)==bool)\n",
" wins += int(this_run_win)\n",
" print('do_switch: %s, wins: %d, count: %d'%(do_switch, wins, count))\n",
" if do_switch:\n",
" assert abs(wins/count - 2/3) < 0.1\n",
" else:\n",
" assert abs(wins/count - 1/3) < 0.1"
]
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"source": [
"Note the above results. You have numerically simulated the Monty Hall problem."
]
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"## Q3\n",
"\n",
"Make a new game where there are 100 doors and the host opens 98 of them after the initial guess. Make a new function called `run_game_100`, and any other functions you need, which plays a single round of this game. Again, this function should take an argument `do_switch`."
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"# YOUR CODE HERE\n",
"raise NotImplementedError()"
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"# This is a test of the above, do not change this code.\n",
"count = 1000\n",
"for do_switch in (True, False):\n",
" wins = 0\n",
" for i in range(count):\n",
" this_run_win = run_game_100(do_switch)\n",
" assert(type(this_run_win)==bool)\n",
" wins += int(this_run_win)\n",
" print('do_switch: %s, wins: %d, count: %d'%(do_switch, wins, count))\n",
" if do_switch:\n",
" assert abs(wins/count - 0.99) < 0.02\n",
" else:\n",
" assert abs(wins/count - 0.01) < 0.02"
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