欢迎来到天天文库
浏览记录
ID:52457858
大小:1.47 MB
页数:45页
时间:2020-03-27
《分析化学Chap2 误差与分析数据处理.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、Chapter2DataHandingandError§2.1ErrorinAnalyticalChemistry§2.2TheDataDistribution§2.3StatisticsProcess§2.4Significantfigures1VOCABULARYPrecision精确度Accuracy准确度Normaldistribution正态分布(((orGaussiacurve)Randomerror随机误差KeyNumber级数Absoluteerror绝对误差MeanError平均误差Relativeerror相
2、对误差DegreeofFreedom自由度Standarddeviation标准偏差Variance方差SystematicError系统误差Mean平均数Median中间数SignificantNumber有效数字Parameter参数Meandeviation平均偏差Datahandling数据处理Distribution分布StatisticalHandling统计处理2§2.1ErrorinAnalyticalChemistry2.1.1ErrorandAccuracy1.Error——Thedifferentbetwe
3、endeterminationxandiμtruevalue.E(AbsoluteError)表示。E=x-μiRE(RelativeError)))x-miRE=´100%m32.AccuracyandErrorThesmallertheerroris,thehighertheaccuracyis.4分析天平称量两物体的质量各为1.6380g和0.1637g,假定两者的真实质量分别为1.6381g和0.1638g,AbsoluteError:(1.6380-1.6381)g=-0.0001g(0.1637-0.1638)g=-
4、0.0001gRelativeError:-0.0001´100%=-0.006%1.6381-0.0001´100%=-0.06%0.163852.1.2Deviationandprecision1.DeviationThedifferentbetweenxandmean.iAbosolutedi:di=xi-xRelatived:ix-xid=´100%rx6AverageDeviation:nn11d=∑di=∑xi-xni=1ni=1RelativeAverageDeviation:dd=´100%rx72.Standa
5、rdDeviationPopulationStandardDeviationn2∑(x-m)i=1s=nSampleStandardDeviationn2(x-x)∑ii=1s=n-1Freedomf=n-182nn∑xi2i=1∑x-i=1ns=n-1s:RelativeStandardDeviationrss=´100%rx又称为变异系数CV(CoefficientofVariation)。93.PrecisionRepeatability(r):Theresultswereobtainedbysameope
6、ratorinsamecondition.Reproducibility(R):Theresultswereobtainedbydifferentoperatorindifferentcondition.10A:2.92.93.03.13.1B:2.83.03.03.03.2xdsA3.00.080.08B3.00.080.14Averagedeviationissame,standarddeviationisdifferent,theprecisionisdifferent.112.1.3Therelationshipbetw
7、eenaccuracyandprecisionprecisionaccuracygoodgoodgoodbadbadbadbadgood12分析铁矿中铁含量,,得如下数据,得如下数据:37.45%,37.20%,37.50%,37.30%,37.25%Calculatemean、averagedeviation、standarddeviation、relativestandarddeviation。37.45%+37.20%+37.50%+37.30%+37.25%x==37.34%5n∑dii=10.11+0.14+0.16
8、+0.04+0.09d==%=0.11%n5n2∑di22222i=1(0.11)+(0.14)+(0.16)+(0.04)+(0.09)s==´100%=0.13%n-15-1s0.13CV==´100%=0.35%x37.34132.1.4Thec
此文档下载收益归作者所有