Yläkvartiiliksi

Yläkvartiiliksi, often abbreviated as UQ, refers to the upper quartile in statistics. It is a value that divides the upper half of a dataset into two equal parts. To find the upper quartile, the data must first be arranged in ascending order. The upper quartile is the median of the upper half of the data. The upper half includes all data points that are greater than or equal to the overall median. If the total number of data points is odd, the median is excluded from both halves when calculating the quartiles. If the total number of data points is even, the data is split exactly in half.

For example, consider the dataset: 1, 3, 4, 5, 6, 7, 8, 9, 10. The median is 6. The upper half of the data is 7, 8, 9, 10. The median of this upper half is the average of 8 and 9, which is 8.5. Therefore, the upper quartile (UQ) for this dataset is 8.5.

The upper quartile is a key component in calculating the interquartile range (IQR), which is the difference between the upper quartile and the lower quartile (LQ). The IQR provides a measure of the spread or variability of the middle 50% of the data. It is less affected by outliers than the range of the entire dataset. The upper quartile is also used in box plots to visually represent the distribution of data.

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