如何在main中使用类中的方法

Question

我创建了一个名为LineOfRegression的方法，我想打印出一个回归的示例线，斜率为0.18784，截距为-7.964。我怎么会在主要的？ （我已粘贴全班以供参考; LineOfRegression方法位于底部）

package com.company;

public class ScatterPlot {
    public Point[]points = null;

    ScatterPlot(Point p){
        points = new Point[1];
        points[0] = p;
    }
    public void addPoint(Point p){
        Point[]temp = null;
        if(points==null || points.length == 0){
            points = new Point[1];
            points[0] = p;
        }
        else{
            temp = new Point[points.length+1];
            //use a for loop to copy points into temp
            for(int i = 0; i < points.length; i++){
                temp[i] = points[i];
            }
            //add the new Point p into the last element
            temp[points.length] = p;
            //copy over temp
            points = temp;
        }
    }
    public boolean removeIndex(int index) {
        //Points is null
        if(points == null){
            return false;
        }
        if(points.length==0){
            return false;
        }
        //Out of bounds index
        if(index >= points.length || index <0){
            return false;
        }

        //{p0 p1 p2 p3 p4 p5} index = 3
        //P0 - P2
        //Copy elements before remove
        Point[] newArray = new Point[points.length-1];
        for(int i = 0; i<index;i++){
            newArray[i] = points[i];
        }
        //Copy elements after remove
        for(int i = index; i<newArray.length; i++){
            newArray[i] = points[i+1];
        }
        points = newArray;
        return true;
    }
    void printReport(){
        System.out.println("Number of points " + points.length);
        System.out.println("Line of Regression is " + lineOfRegression().toStr());
    }
    public Line lineOfRegression(){
        double n = points.length;
        double sigmaX = 0;
        double sigmaY = 0;
        double sigmaXY = 0;
        double sigmaXSquared = 0;

        for(int count = 0; count<= n; count++){
            sigmaX = sigmaX + points[count].getXCoordinate();
            sigmaY = sigmaY + points[count].getYCoordinate();
            sigmaXY = sigmaXY + points[count].getXCoordinate() * points[count].getYCoordinate();
        }
        double slope = (n * sigmaXY) - (sigmaX * sigmaY) / (n + (sigmaXSquared)) - (sigmaXSquared);
        double intercept = (sigmaY - (slope * sigmaX)) / n;

        Line regressionLine = new Line(slope,intercept);
        return regressionLine;
    }
}