Statistics: Mean, Median, Mode and Range
Measures of centre (mean, median, mode) describe the typical value in a data set, while the range measures the spread. These statistics are fundamental tools for summarising and comparing data.
What You Need to Know
Key Concept Diagram
Mean: sum of all values divided by the number of values
Median: the middle value when data is arranged in order; for an even number of values, average the two middle numbers
Mode: the value that appears most often in the data set (there can be more than one)
Range: the difference between the highest and lowest values; measures spread
Outliers are extreme values that can significantly affect the mean but not the median
Key Vocabulary
Mean
The arithmetic average: sum of all values divided by the number of values
Median
The middle value in an ordered data set; not affected by extreme outliers
Mode
The value that appears most frequently in a data set
Range
The difference between the maximum and minimum values in a data set
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Find the mean of: 4, 7, 8, 9, 12
Question 2
Find the median of: 3, 5, 7, 11, 15, 19
Question 3
A class test scores are: 72, 85, 91, 85, 78, 64, 85. What is the mode?
Key Concepts Summary
- ●Mean: sum of all values divided by the number of values
- ●Median: the middle value when data is arranged in order; for an even number of values, average the two middle numbers
- ●Mode: the value that appears most often in the data set (there can be more than one)
- ●Range: the difference between the highest and lowest values; measures spread
- ●Outliers are extreme values that can significantly affect the mean but not the median