-28- 



the data file specified by the variable IFILE and located on unit 21 (disk 

 on DEC-10) . For every species with three or more height trees measured, 

 LINREG fits the following regression model: HEIGHT = B + B * 1/DBH. The 

 following statistics are calculated and stored in common area REG: 



(1) Regression intercept. 



(2) Regression slope. 



(3) Standard error of the regression. 



(4) Number of height trees measured. 



(5) Total number of merchantable trees sampled. 



(6) Average height. 



2 



(7) Coefficient of determination (R ) . 



(8) Mlnimtim diameter of all height trees sampled if less than 8 inches. 

 LINREG ignores cull trees (HEIGHT = 999) . It also checks that input parameters 

 are within the following ranges : 



1 <_ DBH <_ 40 <_ HEIGHT £ 7 if height measured by logs. 



<_ HEIGHT <^ 200 if height measured in feet. 

 If data is found outside these ranges, the value is set to the minimum or 

 maximum of the range. If an illegal species code appears, the tree is ignored 

 and an error message is written to unit 5. 



LINREG also calculates certain statistics for the Softwood, Hardwood and 

 All Species accumulations. These statistics include (3), (4), (5) and (6) 



Description 



Corrected mean height for species 



Corrected number of trees sampled 



Covariance of X and Y 



Diameter at breast height 



Tree height 



DO loop index for reps on input 



Number of reps on input 



Species loop counter 



Forest type code 



Forest type code 



Loop counter 



Mean of X 



Mean of Y 



Corrected mean height for forest types 



