Kvartiilidega

Kvartiilidega is a term used in statistics to refer to the division of a dataset into four equal parts. These divisions are marked by three specific values called quartiles. The first quartile (Q1) is the value below which 25% of the data falls. The second quartile (Q2) is the median of the dataset, meaning 50% of the data falls below it. The third quartile (Q3) is the value below which 75% of the data falls.

The calculation of quartiles typically involves ordering the data from smallest to largest. Once ordered, the median (Q2) is found. Then, the data below the median is considered, and its median is calculated to find Q1. Similarly, the data above the median is considered, and its median is calculated to find Q3. There are slight variations in the exact methods for calculating quartiles, particularly when the number of data points is even.

Quartiles are useful for understanding the spread and distribution of data. They help identify outliers and provide a quick summary of the data's central tendency and dispersion. The interquartile range (IQR), calculated as Q3 - Q1, represents the middle 50% of the data and is a robust measure of variability, less affected by extreme values than the range. They are frequently used in box plots to visually represent the distribution of data.