class_docstr: A set of statistics about a single value series.
class_docstr_tok: ["A","set","of","statistics","about","a","single","value","series","."]
docstr: Standard deviation.
docstr_tok: ["Standard","deviation","."]
code: def dev(self):
      """Standard deviation."""
      if self.num == 0:
          return 0
      return math.sqrt(
          max(0, self.sum_sq / self.num - (self.sum / self.num) ** 2)
      )
  
imports: import collections
  import functools
  import math
  import os
  import sys
  import threading
  import time
label_desc: Use image node_id 5 for calling the Stat obj's underlying member method code with example usage: obj.dev() and returns: math, int