Trimmed Mean spreadsheet functions on variables
VTrimMeanSEM
Description
VTrimMean and VTrimMeanSEM calculate a trimmed mean and the standard error of a trimmed mean.
VTrimMean(k,variable[,filter]) computes the trimmed mean of a variable.
VTrimMeanSEM(k,variable[,filter]) computes the standard error of the trimmed mean of a variable.
If k is equal to or larger than 1 then k will be taken as the number of cases to drop at both sides (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/2) cases will be dropped at both sides, so a total of (n*k) cases will be dropped (if k=0.1 then 10% of cases will be dropped).
Examples
VTrimMean(0.1,Systolic) calculates the trimmed mean of the data for variable Systolic with 10% of cases dropped: 5% at the lower side and 5% at the hiher side.
VTrimMean(3,Systolic) calculates the trimmed mean of the data for variable Systolic with 3 cases dropped at the lower side and 3 cases at the higher side, so a total of 6 cases are dropped.
VTrimMeanHigh
VTrimMeanLow and VTrimMeanHigh calculate the confidence interval of a trimmed mean of a variable.
VTrimMeanLow(k,ci,variable[,filter]) and VTrimMeanHigh(k,ci,variable[,filter]) compute the lower and higher value of the ci% confidence interval of the trimmed mean of a variable.
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.
Note
This function calculates a statistic on a variable. Be careful when you use this function in cells of the columns that correspond to the variable, because this actually adds a value to the variable which can lead to unexpected and faulty results. You can exclude the cell to avoid this.
