text: from simkit.stats import SimpleStatsTally
  from simkit.rand import Exponential
  
  sst = SimpleStatsTally()
  print(sst)
  for i in range(1,10):
      sst.new_observation(i)
  
  print(sst)
  
  sst.reset()
  print(sst)
  rv = Exponential(3.7)
  number = 100000
  for x in range(number):
      sst.new_observation(rv.generate())
  
  print('expected: ' + str(rv.mean))
  print(sst)
  print(sst.mean)
  
  print(sst.halfwidth(.995))
  
  sst.reset()
  
  for x in range(200):
      sst.new_observation(rv.generate())
      print('{n:d} {hw:.4f}'.format(n=sst.count,hw=sst.halfwidth(0.995)))