The median is a measure of central tendency used to describe a dataset's middle value. The median is the middle value if the dataset has an odd number of values. If the dataset has an even number of values, the median is the average of the two middle values.
The formula for calculating the median of a dataset is:
- If the dataset has an odd number of values, n, the median is the following value in the ordered dataset.
$$\frac{n+1}{2}$$
- If the dataset has an even number of values, n, the median is the average of the following two values in the ordered dataset.
$$\frac{n}{2}$$ and $$\frac{n}{2}+1$$
Example 1: To calculate the median of a dataset, you first need to order the values from smallest to largest (or from largest to smallest) and then find the middle value.
For example, if you have the following dataset: 10, 11, 14, 9, 6
To calculate the median of this dataset, you would first need to order the values from smallest to largest: 6, 9, 10, 11, 14
Since this dataset has an odd number of values (5), the median is the middle value (3rd value), which is 10.
In this example, the dataset has an odd number of values. The median is the (5+1)/2 = 3rd value in the ordered dataset, which is 10.
Example 2:
For example, if you have the following dataset: 10, 11, 14, 9, 6, 10
To calculate the median of this dataset, you would first need to order the values from smallest to largest, which gives you the following: 6, 9, 10, 10, 11, 14
Since there are an even number of values in the dataset, the median is the average of the two middle values (3rd and 4th), which are 10 and 10. The average of these two values is 10, so the median of the dataset is 10.
The median is a commonly used measure of central tendency used to describe a dataset's middle value. The median is often used in cases where the mean may be influenced by outliers or extreme values or when a simple measure of the "middle" value is needed.
Comparing Mean and Median
Here are some advantages and disadvantages of using the median over the mean:
Advantages of using the median:
- The median is not affected by outliers or extreme values, while the mean is. This means that the median is a more reliable measure of central tendency when there are outliers in the data.
- The median is easier to understand and interpret than the mean, as it represents the data set's middle value.
Disadvantages of using the median:
- The median is not as sensitive to all the data set's values as the mean. This means that the median may not accurately reflect the entire data distribution.
- It is more difficult to perform mathematical operations with the median than with the mean, as the median is not a value that is calculated from the entire data set.
Using Microsoft Excel
You can use the MEDIAN function to find the median of a set of numbers in Excel. This function takes the form MEDIAN(number1, number2, ...), where number1, number2, etc. are the numbers you want to find the median of. For example, if you have a list of numbers in cells A1 through A5, you could find the median of those numbers using the formula =MEDIAN(A1:A5).