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A note on confidence intervals with extended least squares parameter estimates
- Source :
- Journal of Pharmacokinetics and Biopharmaceutics. 15:93-98
- Publication Year :
- 1987
- Publisher :
- Springer Science and Business Media LLC, 1987.
-
Abstract
- It has previously been shown that the extended least squares (ELS) method for fitting pharmacokinetic models behaves better than other methods when there is possible heteroscedasticity (unequal error variance) in the data. Confidence intervals for pharmacokinetic parameters, at the target confidence level of 95%, computed in simulations with several pharmacokinetic and error variance models, using a theoretically reasonable approximation to the asymptotic covariance matrix of the ELS parameter estimator, are found to include the true parameter values considerably less than 95% of the time. Intervals with the ordinary least squares method perform better. Two adjustments to the ELS confidence intervals, taken together, result in better performance. These are: (i) apply a bias correction to the ELS estimate of variance, which results in wider confidence intervals, and (ii) use confidence intervals with a target level of 99% to obtain confidence intervals with actual level closer to 95%. Kineticists wishing to use the ELS method may wish to use these adjustments.
- Subjects :
- Heteroscedasticity
Statistics as Topic
Statistical parameter
Estimator
Models, Biological
Robust confidence intervals
Confidence interval
Kinetics
Pharmaceutical Preparations
Ordinary least squares
Statistics
Confidence distribution
Pharmacology (medical)
General Pharmacology, Toxicology and Pharmaceutics
CDF-based nonparametric confidence interval
Mathematics
Subjects
Details
- ISSN :
- 0090466X
- Volume :
- 15
- Database :
- OpenAIRE
- Journal :
- Journal of Pharmacokinetics and Biopharmaceutics
- Accession number :
- edsair.doi.dedup.....6b0e066a0ecd3812ba84b1076dcb0d24