Kvartileista

Kvartileista is a statistical measure used to divide a dataset into four equal parts, each containing 25% of the data. It is a type of quantile, specifically the 25th, 50th, and 75th percentiles. The kvartileista is often used to summarize the distribution of a dataset and to identify outliers.

The first quartile (Q1) is the value below which 25% of the data falls. The second quartile (Q2), also known as the median, is the value below which 50% of the data falls. The third quartile (Q3) is the value below which 75% of the data falls. The fourth quartile (Q4) is the maximum value of the dataset.

The interquartile range (IQR) is the difference between the third and first quartiles (Q3 - Q1). It is a measure of the spread of the middle 50% of the data. Outliers can be identified as values that fall below Q1 - 1.5 * IQR or above Q3 + 1.5 * IQR.

Kvartileista is widely used in descriptive statistics, exploratory data analysis, and in the construction of box plots. It provides a quick and easy way to understand the distribution of a dataset and to identify any potential outliers.