La étendue interquartile (IQR) is a statistical measure used to quantify the amount of variation or dispersion in a dataset. Specifically, it represents the range within which the central 50% of the data points lie, effectively providing a way to understand the spread of the data while minimizing the influence of outliers.
Pour calculer l'IQR, tout d'abord, l'ensemble de données est organisé en ordre croissant. Le premier quartile (Q1) est ensuite identifié, qui est la médiane de la moitié inférieure de l'ensemble de données, et le troisième quartile (Q3) est trouvé, qui est la médiane de la moitié supérieure. L'IQR est ensuite calculée en soustrayant Q1 de Q3 :
IQR = Q3 – Q1
The resulting value gives a clear indication of the variability of the data. A smaller IQR suggests that the data points are closely clustered around the median, while a larger IQR indicates a wider spread of values. This metric is particularly useful in identifying outliers, which are defined as data points that fall below Q1 – 1.5 * IQR or above Q3 + 1.5 * IQR.
Dans l’ensemble, l’étendue interquartile est un outil essentiel dans statistiques descriptives, allowing researchers and analysts to summarize and interpret data effectively. It is widely used in various fields, including finance, healthcare, and sciences sociales, to assess distribution des données and inform decision-making.