code: def _max_stat(X, X2, perms, dof_scaling):
      """Aux function for permutation_t_test (for parallel comp)."""
      n_samples = len(X)
      mus = np.dot(perms, X) / float(n_samples)
      stds = (
          np.sqrt(X2[None, :] - mus * mus) * dof_scaling
      )  # std with splitting
      max_abs = np.max(
          np.abs(mus) / (stds / sqrt(n_samples)), axis=1
      )  # t-max
      return max_abs
  
imports: from math import sqrt
  import numpy
  from ..parallel import parallel_func
  from ..utils import check_random_state, logger, verbose
label_desc: Use image node_id 1 for calling a global function with example usage: _max_stat(X, X2, perms, dof_scaling) and returns: max_abs