-52- 



DOUBLE SAMPLING WITH RATIO OF MEANS EXPANSION 



X. = Basal area per acre at cluster 1 



Y = Volume per acre at cluster i, 

 N = Number of possible sample units 

 n = Total number of units sampled 



n = Number of volume units sampled 

 o 



X = Average basal area of all units sampled 



X = Average basal area of the volume units sampled 



Y = Average volume of the volume units sampled 

 o 



Y = Ratio estimate of the mean volume per acre 



Y 



B - -T- 



O 



Y = B • X 



r 



t - C-^X^l (-ii^^^ 4(-^ 



