# Untitled

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Jul 20th, 2020
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1. import matplotlib.pyplot as plt
2.
3. n = 0.5 # number of smoke lovers
4.
5. # some initial values
6. k = 1 # ratio between smoke lovers and non-smoke lovers probabiltiies
7. q = 0.01 # probability non smoke lovers smoke
8. p = k*q  # probability smoke lovers smoke
9.
10. pHist = []
11. qHist = []
12. kHist = []
13.
14. for i in range(10000):
15.     # calculate conditional probabilities
16.     pKilledIfSmokes = p*n / (p*n + q*(1-n))
17.     pKilledIfNoSmokes = (1-p)*n / (1 - p*n + q*(1-n))
18.
19.     # make decision according to EDT
20.     # if smoking is desirable, slightly increase the probability of smoking
21.     # otherwise, decrease it
22.     if -101*pKilledIfSmokes - 1*(1-pKilledIfSmokes) > -100*pKilledIfNoSmokes:
23.         q *= 1.01
24.     else:
25.         q /= 1.01
26.
27.     if -90*pKilledIfSmokes + 10*(1-pKilledIfSmokes) > -100*pKilledIfNoSmokes:
28.         k *= 1.01
29.     else:
30.         k /= 1.01
31.
32.     p = k*q
33.
34.     # record the histories of p, q and k
35.     pHist.append(p)
36.     qHist.append(q)
37.     kHist.append(k)
38.
39. # plot either one
40. # plotting p, q is best when n > 0.9
41. # plotting k is best when n < 0.9
42.
43. """ plt.plot(pHist)
44. plt.plot(qHist)"""
45.
46. plt.plot(kHist)
47. plt.show()