Bravais-Pearson and Spearman Correlation Coefficients: Meaning,Test of Hypothesis and Confidence Interval

Conover W.J. , Iman R.L. Rank transformations as a bridge between parametric and nonparametric statistics. Am Stat 1981; 35: 124–32.

Kenney J.F. , Keeping E.S. Mathematics of statistics – part two. New York: D. Van Nostrand Company, Inc., 1951.

Kramer M.S. Clinical epidemiology and biostatistics. Berlin: Springer-Verlag, 1988.

Dittadi R. , Meo S. , Fabris S. , Gasparini G. , Contri D. , Medici M. , Gion M. Validation of blood collection procedures for determination of circulating vascular endothelial growth factor (VEGF) in different blood compartments. Int J Biol Markers 2001; 16: 87–96.

Bossi A. , Cortinovis I. , Duca P. , Marubini E. Introduzione alla statistica medica. Rome: La Nuova Italia Scientifica, 1992.

Efron B. , Tibshirana R.J. An introduction to the bootstrap. London: Chapman and Hall, 1993.

Carpenter J. , Bithell J. Bootstrap confidence interval: when, which, what? A practical guide for medical statisticians. Stat Med 2000; 19: 1141–64.

SAS Institute Inc. SAS Campus Drive Care, NC 27513, USA.