OCR GCSE Chemistry B · J258
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Evaluating data qualityAn instrument that does not read zero when the true input is zero has a zero error. Calibration against known reference values can reveal some systematic errors. Correct zeroing or calibration may remove them, but simply taking more readings will not: repeated biased values can remain closely grouped and therefore appear very precise.