25 * Implementation of the Chi2 test for 2D histograms.\n
26 * This class is derived from the abstract class JTest_t(). For a general description of the implementation of this and other tests derived from JTest_t(), see its documentation.\n
27 * The parameter slice can have the values x, X, y or Y. The histograms are sliced along the corresponding axis, and the JTestChi2() test is applied to each slice.\n
28 * The input parameter `threshold`, is used to evaluate whether the test is passed or failed for each slice.\n
29 * The evaluation is done by comparing the `threshold` value with the result produced by the Chi2 test for each slice. The output of JTestChi2() is a p-value.\n
30 * The parameter `threshold` should therefore be a real value between 0 and 1.