marknagelberg

import math
import numpy as np
from scipy import stats
import pandas as pd
import seaborn as sns

def z_calc(p1, p2, n1, n2):
    p_star = (p1*n1 + p2*n2) / (n1 + n2)
    return (p2 - p1) / math.sqrt(p_star*(1 - p_star)*((1.0 / n1) + (1.0 / n2)))

marknagelberg

def sample_required(p1, p_diff, alpha):
    if p_diff <= 0:
        raise ValueError("p_diff must be > 0")
    n = 1
    while True:
        z = z_calc(p1, p1+p_diff, n1=n, n2=n)
        p = 1 - stats.norm.cdf(z)
        if p < alpha:
            break
        n += 1

marknagelberg

#Map how sample size changes as choice of p1 changes, holding all 
#else constant.

p1s = [x*.01 for x in range(96)]

data = []
for p1 in p1s:
    record = {}
    record['Probability Difference'] = p_diff
    record['Sample Size to Detect Difference'] = sample_required(p1=p1,

marknagelberg

from matplotlib import pyplot

fig, ax = pyplot.subplots(figsize=(9, 9))
sns.set(style='darkgrid')

plot = sns.pointplot(x='Initial Probability',
            y='Sample Size to Detect Difference',
            hue='Confidence Level', ax = ax,
            data=df)

marknagelberg

#Observe probability difference from 2% to 10%
p_diffs = [x*.01 for x in range(2,11)]

data = []
for p_diff in p_diffs:
    record = {}
    record['Probability Difference'] = p_diff * 100
    record['Sample Size to Detect Difference'] = sample_required(p1=.5,
                                                                p_diff=p_diff,
                                                                alpha=.05)

marknagelberg

from matplotlib import pyplot
fig, ax = pyplot.subplots(figsize=(10, 10))

sns.set(style='darkgrid')

plot = sns.pointplot(x='Probability Difference',
            y='Sample Size to Detect Difference',
            hue='Confidence Level', ax = ax,
            data=df)

marknagelberg

from flask import Flask

app = Flask(__name__)

@app.route('/')
def home():
   return 'Hello World!'

if __name__ == '__main__':
     app.run(debug=True)

marknagelberg

import os

class Config:
    SECRET_KEY = os.environ.get('SECRET_KEY') or 'secret string'


class DevelopmentConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('DEV_DATABASE_URL')

marknagelberg

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from config import config

db = SQLAlchemy()

def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])

marknagelberg

from . import db

class Name(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(128), nullable=False)