Sec. 7.2 



DETERMINING LINEAR TREND LINES 



207 



TABLE 7.23 



Illustration of Some Features of the Method of Least Squares 

 Using Data of Table 7.22 



Sums 12.9226 - 2(F = F) ! 



15.8926 



not obtained by the method of least squares, and as long as sufficient 

 accuracy is kept in the calculations to pick up small differences. 



This is the basis for the statement that the method of least squares 

 makes the standard deviation of the F's from the trend line as small 

 as possible for any straight line, which is a strong argument for the 

 use of this line in practice. 



