SM4.4 Averages and data interpretation
You can compute and reason about averages, including weighted averages and the effect of adding or removing a value, and read tables, bar charts and pie charts quickly and accurately.
Topics shown in module order.
The average is a total in disguise, and treating it as one, total equals average times count, solves the questions that trip people up: what a new student does to a class average, what a wrongly recorded mark did to it, how two groups combine. Data interpretation adds the reading of tables and charts, where the questions are easy percentages hiding behind the effort of finding the right numbers to compare.
Work through these
Solve average questions by writing totals rather than averages wherever a value joins or leaves
Totals add and averages do not, which is the entire secret of this topic. Writing the totals line first turns the new-member and wrong-entry questions from puzzles into subtractions.
Compute weighted averages for two groups of different sizes, and explain why the answer sits nearer the bigger group
A combined average leans toward the larger group, and knowing which way it must lean is a free error check on every such question. The explanation is one sentence about totals, and owning it beats memorising the formula.
Answer a timed set of questions from one table, one bar chart and one pie chart
Data interpretation sections are read-and-compare under time, and the practice is in locating the right cells fast, not in hard arithmetic. Three chart types cover what nearly every paper draws from.
For one chart, write two comparisons the chart supports and one it cannot support
A pie chart of shares says nothing about absolute amounts unless the total is given, and papers test exactly that confusion. Practising what a chart cannot say is the half of chart reading nobody teaches.
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Links last checked 7 Sept 2026.
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