docstr: Tests sample for scale specification.
docstr_tok: ["Tests","sample","for","scale","specification","."]
code: def test_mean_and_scale(self):
      """Tests sample for scale specification."""
      mean = np.array([[1.0, 0.1], [0.1, 1.0]])
      scale = np.array([[0.4, -0.1], [0.22, 1.38]])
  
      covariance = np.matmul(scale, scale.transpose())
      size = 30000
      sample = self.evaluate(
          tff_rnd.mv_normal_sample(
              [size], mean=mean, scale_matrix=scale, seed=7534
          )
      )
  
      np.testing.assert_array_equal(sample.shape, [size, 2, 2])
      np.testing.assert_array_almost_equal(
          np.mean(sample, axis=0), mean, decimal=1
      )
      np.testing.assert_array_almost_equal(
          np.cov(sample[:, 0, :], rowvar=False), covariance, decimal=1
      )
      np.testing.assert_array_almost_equal(
          np.cov(sample[:, 1, :], rowvar=False), covariance, decimal=1
      )
  
imports: from absl.testing import parameterized
  import numpy
  import tensorflow.compat.v2
  import tf_quant_finance
  from tensorflow.python.framework import test_util
label_desc: Use image node_id 6 for calling the RandomTest obj's underlying member method code with example usage: obj.test_mean_and_scale() without return types