AJP - Regulatory, Integrative and Comparative Physiology, Vol 233, Issue 3 94-R99, Copyright © 1977 by American Physiological Society

ARTICLES

Fitting straight lines to experimental data

R. A. Brace

The problem associated with use of statistical methods for determining a best linear relationship of the form Y = AX +B have been examined for a condition quite prevalent with experimental research, i.e., when the values of both variables are subject to essentially unknown errors. Under this condition standard least-squares regression analysis underestimates the value of the slope A. A very simple method for determining the best value of the slope and intercept has been introduced which can be used when errors are present in both variables. With this proposed method, the calculated slope is equal to the standard error of Y divided by the standard error of X (with the appropriate sign) and the intercept is found from the mean values of X and Y, i.e., B = Y - AX. The best estimate of the slope is also equal to the slope found with the conventional regression method divided by the absolute value of the correlation coefficient. The line determined with the suggested method can be considered to be a line of symmetry through the data.

This article has been cited by other articles:

				E. Berggreen and H. Wiig Lowering of interstitial fluid pressure in rat submandibular gland: a novel mechanism in saliva secretion Am J Physiol Heart Circ Physiol, April 1, 2006; 290(4): H1460 - H1468. [Abstract] [Full Text] [PDF]

				S. Masuki, J. H. Eisenach, F. A. Dinenno, and M. J. Joyner Reduced forearm {alpha}1-adrenergic vasoconstriction is associated with enhanced heart rate fluctuations in humans J Appl Physiol, March 1, 2006; 100(3): 792 - 799. [Abstract] [Full Text] [PDF]

				M. Farias III, M. W. Gorman, M. V. Savage, and E. O. Feigl Plasma ATP during exercise: possible role in regulation of coronary blood flow Am J Physiol Heart Circ Physiol, April 1, 2005; 288(4): H1586 - H1590. [Abstract] [Full Text] [PDF]

				S. Yoshikawa, J. A. King, R. N. Lausch, A. M. Penton, F. G. Eyal, and J. C. Parker Acute ventilator-induced vascular permeability and cytokine responses in isolated and in situ mouse lungs J Appl Physiol, December 1, 2004; 97(6): 2190 - 2199. [Abstract] [Full Text] [PDF]

				K. Okazaki, Y.-I. Kamijo, Y. Takeno, T. Okumoto, S. Masuki, and H. Nose Effects of exercise training on thermoregulatory responses and blood volume in older men J Appl Physiol, November 1, 2002; 93(5): 1630 - 1637. [Abstract] [Full Text] [PDF]

				H. Wiig and T. Lund Relationship between interstitial fluid volume and pressure (compliance) in hypothyroid rats Am J Physiol Heart Circ Physiol, September 1, 2001; 281(3): H1085 - H1092. [Abstract] [Full Text] [PDF]

				K. L. Karau, R. H. Johnson, R. C. Molthen, A. H. Dhyani, S. T. Haworth, C. C. Hanger, D. L. Roerig, and C. A. Dawson Microfocal X-ray CT imaging and pulmonary arterial distensibility in excised rat lungs Am J Physiol Heart Circ Physiol, September 1, 2001; 281(3): H1447 - H1457. [Abstract] [Full Text] [PDF]

				W. Long, Y. Zhao, L. Zhang, and L. D. Longo Role of Ca2+ channels in NE-induced increase in [Ca2+]i and tension in fetal and adult cerebral arteries Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R286 - R294. [Abstract] [Full Text] [PDF]

				E. R. Zakaria, J. Lofthouse, and M. F. Flessner In vivo effects of hydrostatic pressure on interstitium of abdominal wall muscle Am J Physiol Heart Circ Physiol, February 1, 1999; 276(2): H517 - H529. [Abstract] [Full Text] [PDF]

				G. Bergstrom, I. Johansson, K. M. Stevenson, M. M. Kett, and W. P. Anderson Perindopril Treatment Affects Both Preglomerular Renal Vascular Lumen Dimensions and In Vivo Responsiveness to Vasoconstrictors in Spontaneously Hypertensive Rats Hypertension, April 1, 1998; 31(4): 1007 - 1013. [Abstract] [Full Text] [PDF]