高等教育：分析化学.ppt

1、Chapter 2Error and DataHandling2. Ways of expressing accuracyAccuracy and Errors Absolute Error（绝对误差） Relative Error（相对误差）2019/12/179 Absolute ErrorEa = X - T Relative Error厂 Ea x-TEr =T TA simple exampleExample 2-1, The results of two analysis are 0.5125g and 5.1250g respectively, the corresponding

2、 true values are 0.5126 and 5.1251g, calculate the Ea and ErEui =05125g0.5126g=O.OOOlgE“2 =5.1250g5.1251g=O.OOOlg如0.00010 02%八 Tx 05126gE 9 O.OOOlgE,=亠= 0.002%T2 51251g3 Ways of expressing PrecisionPrecision and Deviation meanXp x2, x3 , xnX j ，X3 * *，JC n Deviationdi =x -x (/ = 1,2-n) Average Devia

3、tion- = |d,| + |d2| + - + |dn| = XN(2_勺 nn(4) Relative average deviationA simple example巾映量法测定某铜合金中铜的百分含量，得到两批数据，每批有10个。测定的平均值为10.0%o各次测量的偏差分别为:第一批dj:+0.3, -0.2, -0.4*, +0.2, +0.1, +0.4*5 0.0, -0.3,+0.2, -0.3第二批dj:0.0, +0.1,-0.7*, +0.2, -0.1 dHg；5 o、6ocd5OhbHd3H*62HLa3d2Ln9&6d9d2、6OOHHd2c;3hIa5hd2、6

4、9yHd95*65:9c;2g1d3HgIn order to study the regularity of the distribution of meas urement data，According to the following steps to prepare frequency distribution table in order to conduct investigati ons.1. rangeR= 1.74-1.49=0.252. Determine the group number group intervalThe number of group dependin

5、g on sample size ,group intervalrangethe group number1.74-1.499q003For example: 1.48-1.51, 1.51-1.54In order to avoid a group of data points in the twoThat is: 1.4851.515, 1.5151.545, 1.51 in one rangeFrequency（频数）:落在每个组内测定值的数目。Relative frequency（相对频数）濒数与样本容量总数之比。Table. Frequency TablesGroupFrequencyRelative Frequency1.485 1.51522.2%1.515 1.54566.7%1.545 1.57566.7%1.575 1.6051718.9%1.605 1.6352224.4%1.635 1.6652022.2%1.665 1.6951011.1%1.695 1.72566.7%1.725 1.75511.1%z90100%25+205 o Aouanbe5oIn the range of values abscissa（横坐标），draw the frequ