What is important to know about Mean, median, mode & range?

Mean = sum of all values ÷ number of values.

Median = middle value when data is ordered (or mean of middle two for even-sized data).

Mode = most frequently occurring value (there can be more than one).

📊

Statistics & Probability · Foundation & Higher

Mean, median, mode & range

Averages summarise a data set with a single representative value. The range measures spread.

🔑

1Mean = sum of all values ÷ number of values.
2Median = middle value when data is ordered (or mean of middle two for even-sized data).
3Mode = most frequently occurring value (there can be more than one).
4Range = largest value − smallest value.
5The mean is affected by outliers; the median is not.

📐

Mean

x̄ = Σx / n

Σx = sum of all values, n = count

Range

Range = Max − Min

✍️

Example 1

Find the mean, median, mode and range of: 3, 7, 7, 2, 9, 4, 7

Working

AnswerMean ≈ 5.57, Median = 7, Mode = 7, Range = 7

⚠️

✗Forgetting to sort the data before finding the median.

✗Finding the median position incorrectly for even-sized data (should average the two middle values).

✗Confusing mode (most common) with mean (average).

🎯

✓Always sort the data first — write the ordered list out clearly.

✓For n data points, the median is at position (n+1)/2.

Ready to test yourself on Mean, median, mode & range?

Get AI-marked practice questions on exactly this subtopic.

▶️ Watch on YouTube

Free video lessons

Click a topic to search

Opens YouTube — pick any free GCSE video.