presto-main/src/main/java/io/prestosql/operator/aggregation/AggregationUtils.java/AggregationUtils/getRegressionIntercept
class AggregationUtils:    public static double getRegressionIntercept(RegressionState state)
    {
        double slope = getRegressionSlope(state);
        double meanX = state.getMeanX();
        double meanY = state.getMeanY();

        return meanY - slope * meanX;
    }