Creatinine is a breakdown product of creatine phosphate from muscle and proteln metabolism and its blood levels are tested to evaluate kidncy function Your labocatory is evaluating the precision of a new colorimetric method for creatinine analysis of human blood serum in which the sample is reacted with alkaline picrate to produce a eolored product. Rather than perform one set of analyses, several sets with samples from different patients are performed over several days, in order to get a briter entimate of the precision of the method. From the following absorbance data. calculate the nooled standard deviatian for the absorbance readings