Interquartile and Interquantile Ranges

Non-parametric measures of variability.

These measures are useful in Neurofeedback for several reasons

They are:
1) not sensitive to extreme or outlying values
2) a robust measure of variability in open ended distributions
3) ideal for use with skewed distributions

cover art IQR iqr4b

The interquartile range is calculated by finding the difference between the 75th percentile and the 25th percentile. The range can be calculated for the total spectrum or for subsets of the spectrum.