### Question:
MathUtil { public static double ilogit(double x) { return 1 / (1 + Math.exp(-x)); }  static double logit(double p); static double ilogit(double x);  }### Answer:
@Test public void testIlogit() { double[] xarr = {-10, 5, 0, 20, 23.7, 0.3}; for (double x : xarr) { assertEquals(x, MathUtil.logit(MathUtil.ilogit(x)), 0.000001); } }