From: Comparison of estimators of variance for forest inventories with systematic sampling - results from artificial populations
Trend
τij
min(τij)
mean(τij)
max(τij)
Strong
(i + j − 241)/120
–2
0
2
Moderate
(i + j − 241)/240
–1
1
Weak
(i + j − 241)/480
−0.5
0.5