private final double confidence;
public ApproximateSumGroupedAccumulator(int valueChannel, Optional<Integer> maskChannel, Optional<Integer> sampleWeightChannel, double confidence)
{
super(valueChannel, VARCHAR, VARCHAR, maskChannel, sampleWeightChannel);
this.counts = new LongBigArray();
this.samples = new LongBigArray();
this.sums = new LongBigArray();
this.m2s = new DoubleBigArray();
this.means = new DoubleBigArray();
this.confidence = confidence;
}