interquartil

Interquartile refers to a statistical measure that describes the spread of the middle fifty percent of a dataset. It is calculated as the difference between the third quartile (Q3) and the first quartile (Q1). The first quartile, or Q1, is the value below which 25% of the data falls, while the third quartile, or Q3, is the value below which 75% of the data falls. Therefore, the interquartile range (IQR) is Q3 - Q1.

The IQR is a robust measure of dispersion, meaning it is less affected by outliers than measures like the range. Outliers are extreme values that can significantly skew the overall distribution of data. By focusing on the middle portion of the data, the IQR provides a more stable and representative picture of the data's variability.

This measure is frequently used in descriptive statistics to summarize the spread of a dataset and to identify potential outliers. A larger IQR indicates greater variability in the middle of the dataset, while a smaller IQR suggests that the middle values are more clustered together. The interquartile range is a key component in constructing box plots, which visually represent the distribution of data, including quartiles and potential outliers. It is a fundamental concept in understanding the variability of data in a distribution.