What is the middle 50 percent on a box and whisker plot?

The middle 50 percent on a box and whisker plot is represented by the interquartile range (IQR), which is the area between the first quartile (Q1) and the third quartile (Q3). This section contains the central half of the data, where the lower edge of the box corresponds to Q1 (25th percentile) and the upper edge corresponds to Q3 (75th percentile). The box itself visually shows the spread of this middle portion of the dataset, while the whiskers extend to the minimum and maximum values within 1.5 times the IQR.