gistfile1.py

from sympy.statistics import Normal

def getStdDev(distance,confidence,x = Normal(0,1)):
  "Distance = end point - mean"
  confidenceDistance = x.confidence(confidence)[1]
  stddev = confidenceDistance * distance
  return stddev

def confidenceInterval(start,end,confidence):
  """If I give a 50 percent chance that my variable x is between 10 and 13,
  then this function converts that to a Gaussian centered at 11.5 with an
  appropriate standard deviation."""

  mean = 0.5*(end+start)
  stddev = getStdDev(0.5*(end-start), confidence)

  return (mean,stddev)

print confidenceInterval(300,500,0.8)