/** {@inheritDoc} */
public ConfidenceInterval createInterval(int numberOfTrials, int numberOfSuccesses, double confidenceLevel) {
IntervalUtils.checkParameters(numberOfTrials, numberOfSuccesses, confidenceLevel);
final double alpha = (1.0 - confidenceLevel) / 2;
final NormalDistribution normalDistribution = new NormalDistribution();
final double z = normalDistribution.inverseCumulativeProbability(1 - alpha);
final double zSquared = FastMath.pow(z, 2);
final double modifiedNumberOfTrials = numberOfTrials + zSquared;
final double modifiedSuccessesRatio = (1.0 / modifiedNumberOfTrials) * (numberOfSuccesses + 0.5 * zSquared);
final double difference = z *
FastMath.sqrt(1.0 / modifiedNumberOfTrials * modifiedSuccessesRatio *