550 n 



500- 



450 



400 



350 



300 



< 



o 



LU 



o 



z 



LU 

 DC 

 LU 

 Li. 



— 250 

 CI 



LU 



CO 

 < 



I- 



o 



LU 



h- 

 LU 

 Q 



200- 



150 



100- 



50 



4 6 8 10 12 



NUMBER OF REPLICATES 



14 



16 



Reference: Tetra Tech (1 986b) 



Figure E-2 Minimum detectable difference versus number of replicates 

 at selected levels of unexplained variance for 8 and 16 

 stations. Power of test = 0.80, significance level = 0.05. 



