In these two days, we look at the method linear fitting to make the curves smoother. With the distribution of the material, we find that it is necessary to record the position of the point which is in the middle of two points. In this case, it has two middle points when sketching three points from the table. Actually, when connecting the points in real curve, we could connect each point with two noted middle points on the left and right previously to get the smoother line as it may have huge differences or uncertainties when connect three points according to the data in the table. Typically, if a point is theoretically out of the line and has difference if connect the point with two neighbor points, we could connect two middle points obtaining by averaging the value of the point and neighbor point on the left and right respectively.