Desharnais, Brigitte 
ORCID: https://orcid.org/0000-0001-7373-656X, Camirand-Lemyre, Félix ORCID: https://orcid.org/0000-0003-3277-2729, Mireault, Pascal and Skinner, Cameron D.
(2014)
Determination of Confidence Intervals in Non-normal Data: Application of the Bootstrap to Cocaine Concentration in Femoral Blood.
Journal of Analytical Toxicology, 39
(2).
pp. 113-117.
ISSN 0146-4760
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Official URL: https://academic.oup.com/jat/article/39/2/113/7620...
Abstract
Calculating the confidence interval is a common procedure in data analysis and is readily obtained from normally distributed populations with the familiar formula. However, when working with non-normally distributed data, determining the confidence interval is not as obvious. For this type of data, there are fewer references in the literature, and they are much less accessible. We describe, in simple language, the percentile and bias-corrected and accelerated variations of the bootstrap method to calculate confidence intervals. This method can be applied to a wide variety of parameters (mean, median, slope of a calibration curve, etc.) and is appropriate for normal and non-normal data sets. As a worked example, the confidence interval around the median concentration of cocaine in femoral blood is calculated using bootstrap techniques. The median of the non-toxic concentrations was 46.7 ng/mL with a 95% confidence interval of 23.9–85.8 ng/mL in the non-normally distributed set of 45 postmortem cases. This method should be used to lead to more statistically sound and accurate confidence intervals for non-normally distributed populations, such as reference values of therapeutic and toxic drug concentration, as well as situations of truncated concentration values near the limit of quantification or cutoff of a method.
| Divisions: | Concordia University > Faculty of Arts and Science > Chemistry and Biochemistry |
|---|---|
| Item Type: | Article |
| Refereed: | Yes |
| Authors: | Desharnais, Brigitte and Camirand-Lemyre, Félix and Mireault, Pascal and Skinner, Cameron D. |
| Journal or Publication: | Journal of Analytical Toxicology |
| Date: | 20 November 2014 |
| Funders: |
|
| Digital Object Identifier (DOI): | 10.1093/jat/bku127 |
| ID Code: | 986543 |
| Deposited By: | BRIGITTE DESHARNAIS |
| Deposited On: | 25 Mar 2020 15:42 |
| Last Modified: | 25 Mar 2020 15:42 |
References:
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