kvartilem

Kvartil is a statistical term that refers to values that divide a dataset into four equal parts. These divisions are based on the ordered values of the data. There are three main quartiles: the first quartile (Q1), the second quartile (Q2), and the third quartile (Q3).

The first quartile, Q1, also known as the lower quartile, represents the 25th percentile of the data. This means that 25% of the data points are below Q1, and 75% are above it. The second quartile, Q2, is the median of the dataset. It represents the 50th percentile, meaning that 50% of the data is below Q2 and 50% is above. The third quartile, Q3, or upper quartile, represents the 75th percentile. Thus, 75% of the data points are below Q3, and 25% are above.

Quartiles are useful for understanding the spread and distribution of data. The interquartile range (IQR), which is the difference between Q3 and Q1 (IQR = Q3 - Q1), provides a measure of the variability of the middle 50% of the data, making it less sensitive to outliers than the overall range. Quartiles are frequently used in descriptive statistics, box plots, and for identifying potential outliers in a dataset.