def main():
pregnancies = first.get_pregnancies_dataset()
live_pregnancies = [preg for preg in pregnancies.records if preg.outcome == 1]
firsts, subsequents = first.split_one_vs_all(live_pregnancies,
birthord=1)
period_first = first.get_values_for_field(firsts, 'prglength')
period_subsequent = first.get_values_for_field(subsequents, 'prglength')
var_first = thinkstats.Var(period_first)
var_second = thinkstats.Var(period_subsequent)
print('Variance of the first children gestation periods: {} weeks^2'
.format(var_first))
print('\tAnd the sd is {} weeks.'.format(math.sqrt(var_first)))
print('Variance of the subsequent children gestation periods: {} weeks^2'
.format(var_second))
print('\tAnd the sd is {} weeks.'.format(math.sqrt(var_second)))
weights = get_pumpkin_weights()
print('Finding the variance and mean for these pumpkins: {}'
.format(weights))
mu, var = pumpkins(weights)
sd = math.sqrt(var)
print('\tmean = {}\tvariance = {}\tsd = {}'.format(mu, var, sd))
bar_chart(pregnancies)
plot_pregnancy_pmf(pregnancies)
plot_pregnancies_pmf_differences(pregnancies)
def plot_pregnancies_pmf_differences(prg, week_lo=35, week_hi=46):
live_prg = first.get_live_pregnancies(prg)
firsts, subsequents = first.split_one_vs_all(live_prg, birthord=1)
first_prglen = [record.prglength for record in firsts]
subsequent_prglen = [record.prglength for record in subsequents]
fig = plt.figure()
ax = fig.add_subplot(111)
p1 = pmf.MakePmfFromList(first_prglen)
p2 = pmf.MakePmfFromList(subsequent_prglen)
result = {week: 100 * (p1.Prob(week) - p2.Prob(week))
for week in xrange(week_lo, week_hi)}
ax.bar(result.keys(), result.values(), width=1., color='blue')
ax.set_title('Percent differences in probabilities of gestation periods')
ax.set_xlabel('Gestation period(weeks)')
ax.set_ylabel('100(Pfirst - Psubsequent)')
plt.show()
def main():
live = first.get_live_pregnancies(first.get_pregnancies_dataset())
firsts, others = first.split_one_vs_all(live, birthord=1)
pmf_firsts = Pmf.MakePmfFromList(item.prglength for item in firsts)
pmf_others = Pmf.MakePmfFromList(item.prglength for item in others)
pmf_all = Pmf.MakePmfFromList(item.prglength for item in live)
birth_types = ('first babies', 'subsequent babies', 'all live births')
prob_types = ('early', 'on time', 'late')
for i, pmf in enumerate((pmf_firsts, pmf_others, pmf_all)):
for j, f in enumerate((prob_early, prob_on_time, prob_late)):
print('The probability of {} being born {} is {} %'.format(
birth_types[i], prob_types[j], f(pmf) * 100
))
risks = get_relative_risks(pmf_firsts, pmf_others)
print()
for prob_type in prob_types:
print('The relative risk of first babies to others arriving {} is {}'
.format(prob_type, risks[prob_type]))
def bar_chart(pregnancies):
live_pregnancies = first.get_live_pregnancies(pregnancies)
firsts, seconds = first.split_one_vs_all(live_pregnancies, birthord=1)
period_first = first.get_values_for_field(firsts, 'prglength')
period_second = first.get_values_for_field(seconds, 'prglength')
hist1 = pmf.MakeHistFromList(period_first)
hist2 = pmf.MakeHistFromList(period_second)
fig = plt.figure()
ax = fig.add_subplot(111)
width = 0.35
x1, y1 = hist1.Render()
x2, y2 = hist2.Render()
r1 = ax.bar(x1, y1, width, color='blue')
r2 = ax.bar(np.array(x2) + width, y2, width, color='grey')
ax.set_xlabel('Gestation period(weeks)')
ax.set_ylabel('Frequency')
ax.set_title('Comparison of the gestation periods of first and subsequent'
' babies')
ax.legend((r1[0], r2[0]), ('First Babies', 'Subsequent Babies'))
plt.show()
def plot_pregnancy_pmf(prg):
live_prg = first.get_live_pregnancies(prg)
firsts, subsequents = first.split_one_vs_all(live_prg, birthord=1)
first_prglen = [record.prglength for record in firsts]
subsequent_prglen = [record.prglength for record in subsequents]
fig = plt.figure()
ax = fig.add_subplot(111)
width = 0.35
p1, p2 = map(pmf.MakePmfFromList, (first_prglen, subsequent_prglen))
x1, y1 = p1.Render()
x2, y2 = p2.Render()
r1 = ax.bar(x1, y1, width, color='blue')
r2 = ax.bar(np.array(x2) + width, y2, width, color='grey')
ax.set_xlabel('Gestation period(weeks)')
ax.set_ylabel('Probability')
ax.set_title('Comparison of the gestation periods of first and subsequent'
' babies')
ax.legend((r1[0], r2[0]), ('First Babies', 'Subsequent Babies'))
plt.show()
it has not happened before it.
Args:
pmf(Pmf.Pmf): The PMF of pregnancies.
'''
my_pmf = pmf.Copy()
for value in my_pmf.Values():
if value < week:
my_pmf.Remove(value)
my_pmf.Normalize()
return my_pmf.Prob(week)
if __name__ == '__main__':
live_pregnancies = get_live_pregnancies(get_pregnancies_dataset())
firsts, others = split_one_vs_all(live_pregnancies,
birthord=1)
first_durations = [record.prglength for record in firsts]
others_durations = [record.prglength for record in others]
first_pmf = Pmf.MakePmfFromList(first_durations)
others_pmf = Pmf.MakePmfFromList(others_durations)
fig = plt.figure()
sp = fig.add_subplot(111)
# weeks1, weeks2 = (range(min(first_durations), max(first_durations)),
# range(min(others_durations), max(others_durations)))
weeks1, weeks2 = map(lambda t: range(*t), ((36, 45), (36, 45)))
probs_first = [probability_of_birth_in_week(first_pmf, week)
for week in weeks1]
probs_others = [probability_of_birth_in_week(others_pmf, week)
for week in weeks2]
r1 = sp.plot(weeks1, probs_first, color='b')
r2 = sp.plot(weeks2, probs_others, color='r')
