charting:tableau:functions:median

A median is the middle number in a sorted list of digits. First of all, the numbers must be arranged in value order from lowest to highest. If there is an uneven amount of numbers, the median value is the number in the middle, with the same amount of numbers lower and higher. If the list of numbers is even amount, the middle pair must be set, added together and divided by two to find the median. The median can be used to define an approximate average. The median is the “item in the middle”. But what’s the difference between median and average?

Difference median and average:

- 1, 2, 4, 8, 100

The “middle” of these numbers are 4. The average of 23 is although in the “middle” of the list. But 23 doesn´t represent the spread. The value 100 is an outlier and distorts the average. It´s more representative when the value is closer to the value 4 than at the 100. The median solves this problem by using the number in the middle of the sorted list. If the list of numbers is even amount, the middle pair must be set, added together and divided by two to find the median. The median of 1, 2, 3, 4 is 2.5 Records like incomes are often given of the median, because we want an insight of the middle of the incomes. Few people earn some billion extra and increase the average income, but it is not representative to the income of all regular people and how it changed. The following list shows the advantages and disadvantages of the median:

**Advantages:**

- Very big and very small values do not affect it
- It can be determined for ratio, interval and ordinal scale
- Handles outliers well (often the most accurate representation of a group)
- Splits data into two groups, each with the same number of items

**Disadvantages:**

- In some ways it can be harder to calculate – need to sort the list first
- Communication problems - people may think you mean with average
- May be not so informative (1, 1, 2, 2, 2, 2, 5, 6, 9, 9, 10) – the value of 2 is not representing this sample as a whole very well

charting/tableau/functions/median.txt · Last modified: 2016/05/31 17:39 by hugger