Basic statistical tests - inter-quartile range

Definition

The interquartile range (the range between the 25th and 75th percentile of a dataset) is the standard non-parametric measure of spread, used alongside the median for data that is skewed or not normally distributed, where mean and standard deviation would be misleading summary measures
The interquartile range is based on the middle 50% of the data (between the 25th and 75th percentiles), making it resistant to the influence of extreme outlier values in a way that standard deviation is not - this outlier-resistance is precisely why it is preferred over standard deviation for skewed data with potential extreme values

3 more sections, plus exam facts

Premium unlocks every note across every specialty, and the full exam fact library behind it.