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: - If you have an odd number of data points, the median is the middle value. - 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: * 15, 20, 10, 25, 30 * 7, 12, 5, 9, 18, 13 * 4, 8, 2, 10, 12, 6, 14

2. 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?