TY - JOUR
AU - Hatfield, Jeff S.
AB - June 1990 OTES A D COMME TS Ecology, 71(3), 1990, pp. 1217-1220 3, 4, and 7 and the assumption that the E/S are normally © 1990 by the Ecological Society of America distributed show that 2 2 Var(A ) = k2A/P+ [1 + r(i - 1)]2P+ , (8) under model I, and POWER CALCULATIONS AND (9) MODEL SELECTION FOR TREND ANALYSIS: A COMMENT under model 2. In the remainder of this paper we use v; to denote Var(A ) (for model I) or Var(ln A ) (for William A. Link and JeffS. Hatfield model2). The parameter of interest for the trend analysis is Models f-or changes in the size of animal populations the "slope" parameter from models 5 and 6 , namely are central to ecological research and wildlife manage­ b = A,r, (for model 1), (10) ment. Two frequently used models are the linear model and the exponential model, given by or (I) b = ln(l + r), (for model 2), (II) and which is estimated using the usual methods of least squares. The null hypothesis of no trend (r = 0) is tested In A, = In A, + ~,, i = I, 2, ... , n, 
TI - Power Calculations and Model Selection for Trend Analysis: A Comment
JF - Ecology
DO - 10.2307/1937393
DA - 1990-06-01
UR - https://www.deepdyve.com/lp/wiley/power-calculations-and-model-selection-for-trend-analysis-a-comment-0Y4NKB0f56
SP - 1217
EP - 1220
VL - 71
IS - 3
DP - DeepDyve
ER -