Confidence limits of the geometric mean for a log-normal distribution

Confidence intervals can be used as a test for systematic errors as shown in the following example. 

The absorbance scale of a spectrometer is tested at a particular wavelength with a standard solution which has an absorbance given as 0.470. Ten measurements of the absorbance with the spectrometer give 1 = 0.461, and s = 0.003. Find the 95% confidence interval for the mean absorbance as measured by the spectrometer, and hence decide whether a systematic error is present. 

The 95% confidence limits for the absorbance as measured by the spectrometer are [equation (2.9)]  

Since the confidence interval does not include the known absorbance of 0.470, it is likely that a systematic error has occurred. 

In practice the type of problem in Example 2.9.1 is usually tackled by a different, but related, approach (see Example 3.2.1). 

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Confidence limits of the geometric mean for a log-normal distribution 31... 

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