# Trimmed Mean functions

TrimMeanSEM

## Description

TrimMean and TrimMeanSEM calculate a trimmed mean and the standard error of a trimmed mean.

**TrimMean**(k,range) computes the trimmed mean of the contents of the cells in the specified range.

**TrimMeanSEM**(k,range) computes the standard error of the trimmed mean of the contents of the cells in the specified range.

If **k is equal to or larger than 1** then k will be taken as the number of cases to drop at each side (if k=1 then 2 cases will be dropped in total).

If **k is smaller than 1** then k will be taken as a proportion and *n×k* cases will be dropped at each side, so a total of *2×n×k* cases will be dropped. For example, if k=0.1 then 10% of cases will be dropped at each side; 20% of cases will be dropped in total).

See Calculation of Trimmed Mean, SE and confidence interval for computational details.

The argument range can be a list of numbers, cell addresses, cell ranges (such as A1:A10).

Range can also be a matrix. In that case the function returns a matrix with one row and the same number of columns, with each element the function of the corresponding column. If Range is a row matrix, it is converted to a column matrix first.

## Examples

TrimMean(0.1,A1:A100) calculates the trimmed mean of the data in range A1:A100 with 10% of cases dropped at each side: 10% at the lower side and 10% at the higher side.

TrimMean(3,A1:A100) calculates the trimmed mean of the data in range A1:A100 with 3 cases dropped at the lower side and 3 cases at the higher side, so a total of 6 cases are dropped.

## Calculator

TrimMeanHigh

TrimMeanLow and TrimMeanHigh calculate the confidence interval of a trimmed mean.

TrimMeanLow(k,ci,range) and TrimMeanHigh(k,ci,range) compute the lower and higher value of the ci% confidence interval of the trimmed mean of the contents of the cells in the specified range.

The confidence interval ci must be given in the range 0..100. A value of 95 will give the values of a 95% confidence interval.