Method: Enumerable#mean_stdev

Defined in:
ext/enumerable/statistics/extension/statistics.c

#mean_stdev(population: false) ⇒ mean, stdev

Calculate a mean and a standard deviation of the values in enum. The first element of the result array is the mean, and the second is the standard deviation.

This method is equivalent to:

def mean_stdev(population: false)
  m, v = mean_variance(population: population)
  [m, Math.sqrt(v)]
end

Returns:



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# File 'ext/enumerable/statistics/extension/statistics.c', line 1523

static VALUE
enum_mean_stdev(int argc, VALUE* argv, VALUE obj)
{
  struct variance_opts options;
  VALUE opts, mean, variance;
  size_t ddof = 1;

  rb_scan_args(argc, argv, "0:", &opts);
  get_variance_opts(opts, &options);
  if (options.population)
    ddof = 0;

  enum_mean_variance(obj, &mean, &variance, ddof);
  VALUE stdev = sqrt_value(variance);
  return rb_assoc_new(mean, stdev);
}