Even when only a qualitative answer is required, quantitative methods are often
used to obtain it. In reality, an analyst would never simply report ‘I can/cannot
detect boron in this water sample’. A quantitative method capable of detecting
Major topics covered in this chapter
• Errors in analytical measurements
• Gross, random and systematic errors
• Precision, repeatability, reproducibility, bias, accuracy
• Planning experiments
• Using calculators and personal computers
Introduction
2 1: Introduction
boron at, say, 1g ml-1 levels would be used. If it gave a negative result, the outcome
would be described in the form, ‘This sample contains less than 1 g ml-1 boron’. If
the method gave a positive result, the sample will be reported to contain at least
1g ml-1 boron (with other information too – see below). More complex approaches
can be used to compare two soil samples. The soils might be subjected to a particle
size analysis, in which the proportions of the soil particles falling within a number,
say 10, of particle-size ranges are determined. Each sample would then be characterised
by these 10 pieces of data, which can be used (see Chapter 8) to provide a
quantitative rather than just a qualitative assessment of their similarity.