# TRIMMEAN

Formulas / TRIMMEAN
Calculate the mean of a data set while excluding outliers.
`TRIMMEAN(array, percent)`
• array - an array of data values
• percent - [OPTIONAL] the percentage of values to discard from an array

## Examples

• `=TRIMMEAN(A2:A12, 0.2)`

In this example, array is the data set you wish to calculate the mean for, and percent is the percentage of data points you wish to exclude from the calculation. For example, if we have a data set in A2:A12, and we want to exclude 20% of the data points, use the formula above.

• `=TRIMMEAN(A2:A12, 0.4)`

The TRIMMEAN function can be used to calculate the mean of a data set excluding outliers. This is especially useful if you are trying to calculate the mean of a data set with many outliers, since they can skew your results. For example, say we have a data set in A2:A12 with the following values: 10, 12, 13, 15, 20, 30, 38, 45, 50, 52, 55, and 60. The mean of this data set would be 31.7, but this is skewed by the outliers (30, 38, 45, 50, 52, 55, and 60). To calculate the mean without the outliers, we would use the TRIMMEAN function like above. This would calculate the mean of the data set, excluding 40% of the data points (the outliers). The resulting mean would be 14.25.

• `=TRIMMEAN(A2:A12, 0.2)`

The TRIMMEAN function can also be used to calculate the mean of a data set that includes negative values. For example, say we have a data set in A2:A12 with the following values: -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The mean of this data set would be 4.5. However, if we wanted to exclude 20% of the data points, we could use the TRIMMEAN function like in the example. This would calculate the mean of the data set, excluding the 20% of the outliers.

## Summary

The TRIMMEAN function is a useful tool for excluding outlying data from an analysis. It excludes a percentage of data points from the top and bottom of a data set to provide a more accurate representation of the data.

• The TRIMMEAN function calculates the average by excluding data points from the top and bottom of a data set, meaning it excludes 10% of the data.
• The TRIMMEAN function works by excluding 20% of the data, both from the top and bottom.
• This function is useful when outliers are present in the data that might otherwise skew the mean. 