STANDARD-ERROR ESTIMATES FOR RATES OF CHANGE FROM INDIRECT MEASUREMENTS

When indirect measurements are used to obtain rate-of-change data, an additional source of uncertainty is introduced that must be taken into account in the mean-rate and standard-error estimates. A procedure to account for this uncertainty is described. The chain rule of differen tiation is used to decompose the rate into the product of calibration and Primary experiment parts. Mean-rate and standard-error estimates a re then obtained in terms of the component means and standard errors. The procedure is demonstrated by an analysis of some fatigue-crack-gro wth data.