Estimating the Reliability of the Data The data from these experimen were anal using the statistical methods described in Chapters 5- 8. For each of the standard arsenic solutions and the deer samples, the average of the th absorbance measurements was calculated. The average of the three absorbance for the replicates is a more reliable measure of he concentration of arsenic than a single measurement. Least squares analysis of the standard data (see Section 8D was used o find the best straigh ne among the points and to calculate the concentrations of the unknown sam ples along with their statistical uncertainties and confidence limits,