code: def standard_variance(data, period):
      
      catch_errors.check_for_period_error(data, period)
      sv = [np.var(data[idx+1-period:idx+1], ddof=1) for idx in range(period-1, len(data))]
      sv = fill_for_noncomputable_vals(data, sv)
  
      return sv
docs: Standard Variance.
  
      Formula:
      (Ct - AVGt)^2 / N