Confidence intervals for a crop yield-loss function in nonlinear regression

Technical Report · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5897424

Lee, E H; Tingey, D T; Hogsett, W E

Quantifying the relationship between chronic pollutant exposure and the ensuring biological response requires consideration of nonlinear functions that are flexible enough to generate a wide range of response curves. The linear approximation interval estimates for ozone-induced relative crop yield loss are sensitive to parameter curvature effects in nonlinear regression. The adequacy of Wald's confidence interval for proportional response is studied using the nonlinearity measures proposed by Bates and Watts (1980), Cook and Goldberg (1986), and Clarke (1987a b) and the profile t plots of Bates and Watts (1988). Numerical examples comparing Wald's, likelihood ratio, the bootstrap, and Clarke's adjusted 95% confidence intervals for relative crop yield loss are presented for a number of ozone exposure studies conducted by the National Crop Loss Assessment Network (NCLAN) program. At ambient levels of ozone concentration, the effects of nonlinearity were significant and invalidated the adequacy of Wald's confidence interval. Depending upon the severity of the curvature effects, an alternative interval (i.e., Clarke's adjustment to Wald's interval or the likelihood ratio interval) for proportional yield loss should be considered.

• Research Organization: NSI Technology Services Corp., Corvallis, OR (USA)
• OSTI ID: 5897424
• Report Number(s): PB-91-146506/XAB; CNN: EPA-68-C8-0006
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
560300 -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
CHRONIC EXPOSURE
CROPS
DOSE-RESPONSE RELATIONSHIPS
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL EFFECTS
GROWTH
MATHEMATICAL MODELS
OZONE
PLANT GROWTH
POLLUTION
PRODUCTIVITY
TOXICITY