NOTE A4.2—The slope can have a dramatic influence on precision for
some samples, typically those containing oxygenates, and the calculated
precision obtained using the values in Table A4.3 may not reflect this in
all cases. This can be due to the changing composition of the sample,
causing the slope to change rapidly over a short interval. This change may
occur either during the data increments prior to, or subsequent to, the data
point under calculation.