Occasionally one reads that the mean value of the pH values can be calculated via the geometric mean. The example with the 20 values from the calculator should show that this does not give correct results:

Values: 6.08 6.8 6.77 6.48 6.34 6.99 7.29 6.34 6.26 6.44 6.83 6.75 6.53 6.83 6.43 7.5 6.82 6.77 6.32 6.49 6.54

Outlier according to z-score analysis: 6.08

Comparison of different mean value procedures with and without consideration of the outlier
Mean: arithmetic pH median geometric harmonic
with outlier 6.65 6.54 6.54 6.64 6.63
without outlier 6.68 6.58 6.65 6.67 6.66

Since the pH value is a logarithmic number, the seemingly small differences are not to be classified as irrelevant.

Contact

Prof. Dr Christian Wolkersdorfer

German Address South African Address

christian@wolkersdorfer.info
www.wolkersdorfer.info

IMPRESSUM

The small print …

Go to top