code: def make_data(n=10, mask_shape=(10, 10, 10), axis=0):
      mask = np.zeros(mask_shape, int)
      XYZ = np.array(np.where(mask == 0))
      p = XYZ.shape[1]
      data = np.random.randn(n, p)
      vardata = np.random.randn(n, p) ** 2
      if axis == 1:
          data = data.T
          vardata = vardata.T
      return data, vardata, XYZ
  
file_path: nipy/nipy/labs/group/tests/test_permutation_test.py
imports: import unittest
  import numpy
  from numpy.testing import assert_array_equal
  from nipy.algorithms.graph import wgraph_from_3d_grid
  from ..None import permutation_test
label_desc: Use image node_id 1 for calling a global function with example usage: make_data(n, mask_shape, axis) and returns: data,  vardata,  XYZ