Miðgildið

Miðgildið, often translated as the median, is a statistical measure representing the middle value in a dataset that has been ordered from least to greatest. To find the miðgildið, one must first arrange all the numbers in the set in ascending order. If there is an odd number of data points, the miðgildið is simply the single value in the exact middle of the ordered list. For instance, in the dataset 2, 5, 8, 11, 14, the miðgildið is 8.

If the dataset contains an even number of data points, there are two middle values. In this case, the miðgildið is calculated by taking the average of these two middle numbers. For example, in the ordered dataset 3, 6, 9, 12, 15, 18, the two middle values are 9 and 12. Their average, (9 + 12) / 2 = 10.5, is the miðgildið.

The miðgildið is a robust measure of central tendency, meaning it is not significantly affected by extreme outliers or unusually large or small values in the dataset. This makes it a useful alternative to the mean (meðaltal) when dealing with skewed distributions. For example, in a list of incomes, a few very high incomes would pull the mean higher, while the miðgildið would still represent the income of the typical person more accurately. It provides a good indication of where the "center" of the data lies without being distorted by extreme values.