Calculate a trimmed mean that discards extreme values before averaging.
Trimming a fixed percentage from each tail makes the mean resistant to outliers while retaining more information than the median. A 10 per cent trim tolerates up to 10 per cent contaminated data. Trimmed means are standard in competition scoring and price indices precisely because they resist both accidental and deliberate extreme values.
Trimmed Mean
Trimmed mean = mean of the values remaining after discarding the top and bottom p%
Trimmed mean = mean of the values remaining after discarding the top and bottom p% Trimming a fixed percentage from each tail makes the mean resistant to outliers while retaining more information than the median. A 10 per cent trim tolerates up to 10 per cent contaminated data.
Trimmed means are standard in competition scoring and price indices precisely because they resist both accidental and deliberate extreme values.
This calculator takes 4 inputs: Sample size, Percentage trimmed from each tail, Mean of the full sample, Sum of the retained values. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.