170901 Riddler Express

calculate_bs.py

'''
https://fivethirtyeight.com/features/is-your-friend-full-of-it/
Riddler Express

From Shaun Raviv, a tall tale on the basketball court:

You’re hanging out with some friends, shooting the breeze and talking sports.
One of them brags to the group that he once made 17 free throws in a row after years of not having touched a basketball.
You think the claim sounds unlikely, but plausible. Another friend scoffs, thinking it completely impossible.
Let’s give your bragging friend the benefit of the doubt and say he’s a 70-percent free-throw shooter.

So, who’s right? What is the number of free throws that a 70-percent shooter would be expected to take
before having a streak of 17 makes in a row?

And what if his accuracy was a bit worse?
'''

def calculate_bs(throw_chance, number_of_throws):
    chance_of_happening = throw_chance**number_of_throws
    typical_throws_needed = 1 / chance_of_happening
    return typical_throws_needed


generous_throw_chance = .7
bad_throw_chance = .35
number_of_throws = 17

# 70% throw chance
print(calculate_bs(generous_throw_chance, number_of_throws))
# 429.866… tries Friend COULD be right, but unlikely.

# 35% throw chance
print(calculate_bs(bad_throw_chance, number_of_throws))
# 56,343,425 tries. Friend is full of BS or is rediculously lucky.