EDEXCEL GCSE FOUNDATION MATHS - What is the Median

Edexcel GCSE Foundation Maths - What is the Median?

The median is a measure of central tendency that represents the middle value in a set of data when arranged in order. It's useful for understanding the "typical" value in a dataset, especially when dealing with skewed distributions.

Steps to find the Median:

1. Order the Data: Arrange your data points in ascending order (from smallest to largest).

2. Find the Middle Value:

3. If you have an odd number of data points, the median is the middle value.
4. If you have an even number of data points, the median is the average of the two middle values.

Example 1: Odd Number of Data Points

Let's say we have the following data set: 2, 5, 8, 10, 12

1. Order the Data: 2, 5, 8, 10, 12
2. Find the Middle Value: The middle value is 8. Therefore, the median of this data set is 8.

Example 2: Even Number of Data Points

Let's say we have the following data set: 3, 6, 9, 11, 14, 17

1. Order the Data: 3, 6, 9, 11, 14, 17
2. Find the Average of the Middle Values: The two middle values are 9 and 11. Their average is (9 + 11) / 2 = 10. Therefore, the median of this data set is 10.

Key Points:

• The median is less affected by outliers (extreme values) compared to the mean.
• It's a good measure of central tendency for data sets with skewed distributions.
• It's easy to calculate, even for large datasets.

Practice:

1. Find the median of the following data sets:
2. 15, 20, 10, 25, 30
3. 7, 12, 5, 9, 18, 13

4. 4, 8, 2, 10, 12, 6, 14

5. Explain why the median is a better measure of central tendency than the mean for a data set with a large outlier.

Challenge:

Research and understand the difference between the median and the mean. When would you use each measure?