70 point Acetic acid curve by GC/FID demonstrates heterogeneity of variance in analytical data

These data are from a calibration of Acetic acid on a GC/FID instrument with a headspace autosampler with 70 calibrated points (10 points were targeted for each level, but replicates were weighed individually resulting in 70 unique amount points measured in mg). One major outlier was added after the fact to illustrate how outliers can pull the calibration model. These data illustrate problems with analytical data from chromatography experiments that largely go unnoticed because there's not enough data collected to see them, namely non-normal error, heteroscedasticity, and outliers. There are 8 columns in the dataset, called "Level", "Amount", "Response", "ISArea", "DMIAmt", "STDAmt", "ISAmt", "ISAmount". "Level" contains integer values corresponding to the specific vial prepared, numbered 1:70, not in that order. "Amount" contains the amount of Acetic acid, in mg, in each vial run on the instrument, which was injected into the vial from a stock standard solution with a weighed concentration of Acetic acid and DMI. These data are sorted by "Amount". "Response" is the gas chromatograph's (GC's) resulting area counts for the Acetic acid peak on each run. "ISArea" is the GC's resulting area counts for the Ethylbenzene peak on each run. The "Amt" columns are the balance weights for the internal standard solution, the reagent (DMI), and the stock standard solution added to each vial, measured in mg. These are not the Amounts of the individual standards in a vial. "ISAmount" is the Amount of Ethylbenzene in the vial in mg.本数据集源自使用顶空自动进样器（headspace autosampler）配合气相色谱-氢火焰离子化检测器（GC/FID）对乙酸（Acetic acid）开展的校准实验，共设置70个校准点：每个浓度水平预设10个重复样本，但因每个重复样本均单独称重，最终得到70个以毫克（mg）为单位的独立进样量实测值。后续额外加入1个异常值，用于演示异常值如何偏移校准模型。本数据集直观展现了色谱分析实验中极易被忽视的分析数据问题——由于采集的数据量不足，难以察觉非正态误差、异方差性以及异常值等问题。该数据集共包含8列，分别为"Level"、"Amount"、"Response"、"ISArea"、"DMIAmt"、"STDAmt"、"ISAmt"、"ISAmount"。"Level"列存储整数型数值，对应每个制备完成的进样瓶编号，编号范围为1至70，但并非按顺序排列。"Amount"列存储每个进样瓶中乙酸的实际含量（单位：mg），该含量由已知称重浓度的乙酸与DMI储备标准溶液移取配制得到。数据集已按"Amount"列的值进行排序。"Response"列为每次实验中气相色谱仪（GC）针对乙酸峰得到的峰面积计数结果。"ISArea"列为每次实验中气相色谱仪针对乙苯（Ethylbenzene）峰得到的峰面积计数结果。带"Amt"后缀的三列分别为内标溶液、试剂（DMI）以及储备标准溶液加入每个进样瓶时的天平称重值（单位：mg），其并非单个进样瓶中各标准物质的实际含量。"ISAmount"列为每个进样瓶中乙苯的实际含量（单位：mg）。