### Question:
TransactionTimePDF implements ConditionalProbabilityDensityFunction<Double, Double> { public double probability(Double proposedTime, Double lastTransactionTime) { if(proposedTime >= lastTransactionTime) { return 1.0; } return 0.0; }  double probability(Double proposedTime, Double lastTransactionTime);  }### Answer:
@Test public void testProbability() throws Exception { TransactionTimePDF pdf = new TransactionTimePDF(); assertEquals(pdf.probability(0.5, 0.75), 0.0, 0.000001); assertEquals(pdf.probability(0.5, 0.5), 1.0, 0.000001); assertEquals(pdf.probability(0.75, 0.5), 1.0, 0.000001); }