The Third Quartile (Q3) is a statistical measure that represents the value below which 75% of a data set falls. It is a key component in descriptive statistics, helping to summarize and understand the distribution of data. To find Q3, you first arrange the data in ascending order and then identify the median of the upper half of the data set. In a box plot, the Third Quartile is depicted as the right edge of the box, indicating the spread of the highest 25% of the data. This measure is useful in various fields, including finance and education, to assess performance and identify outliers in data sets.