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Read attitude and apply the author's claims: retrieval: a separate sample with explanations after your response.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
Read attitude and apply the author's claims: retrieval: attempt the attitude and application sample without worked examples. Use the target of each question to decide which information matters, and record your initial response before reading its explanation.
Suppose every reading in one batch has the same positive offset added to it. According to paragraph 3, which comparison is preserved?
[1] A fictional laboratory measures the concentration of a compound in water samples collected over several years. Before each batch, technicians test a stored reference sample and adjust the instrument so that it reports the reference's assigned value. This procedure is intended to separate changes in the collected water from changes in the instrument's response. When the corrected records show a gradual increase in concentration, the laboratory initially regards the regular reference checks as a reason to trust the trend.
[2] A later audit discovers that the stored reference slowly loses some of the compound through a reaction with its container. If technicians continue to assign it the old value, their corrections can make the instrument report progressively higher values for unchanged field samples. The reference is not merely a witness to instrument drift; once its value is treated as fixed, its own changes can enter the corrected measurements. Passing a reference check is therefore not independent evidence against this particular error. It is what the correction procedure was designed to ensure.
[3] This discovery does not establish that the field concentration stayed constant. Both the reference and the field samples may have changed. Nor does it make every comparison within the record useless. If samples from two locations were measured in the same batch under the same correction, some differences between them may remain informative even though the absolute values require revision. Whether a particular comparison survives depends on how the correction affects the quantity being compared. A common added offset leaves a difference unchanged; a common multiplying factor does not leave the numerical difference unchanged, though it may preserve the ratio.
[4] To investigate the long-term trend, the audit recommends testing independently prepared references and remeasuring any preserved field samples whose stability can be established. Those qualifications matter. A newly prepared reference with an independently established concentration can help assess the current instrument, but it cannot by itself reconstruct every past reference value. A preserved field sample that has also changed cannot simply serve as a window onto its original concentration. The laboratory should reconstruct the chain connecting reported numbers to stable comparisons, identify which links can be checked, and report the remaining uncertainty. A correction is evidence of care in procedure; it is not a guarantee that the quantity used to anchor the procedure remained constant.
Review the attitude and application decisions in this reading comprehension sample. Identify the particular restriction or evidence that changed your answer, and return to the corresponding worked lesson before trying a new case.