Read a table or chart in context and summarize a small data set. Distinguish mean, median, and range instead of expecting one number to tell the whole story.
Identify what a display measures and how it is scaled.
Calculate mean, median, and range for a small numerical data set.
Explain why a summary needs context and information about variation.
Read what the display actually measures
Check the title, labels, units, sample, and scale. A count, a percentage, and a measurement answer different questions even if their graphs have similar shapes.
Choose the summary that fits the question
The mean shares the total equally across observations. The median is the middle value after ordering the data. For an even number of observations, add the two central values and divide by 2. The range measures the distance between the largest and smallest values.
A mistake to avoid
An average can hide variation or an unusual observation. A cropped axis can also exaggerate a visual difference. Inspect the underlying values and context before extending the conclusion.
Worked example
Summarize 2, 4, 6, and 10
The total is 22, so the mean is 22 ÷ 4 = 5.5. The middle two values are 4 and 6, giving a median of (4 + 6) ÷ 2 = 5. The range is 10 − 2 = 8. The larger observation raises the mean above the median.
Learning paths that include this skill
Choose the route that fits your goal. The same skill can be useful in more than one subject or stage of learning.