Mean, Median & Mode

These three 'measures of central tendency' summarise a data set in a single representative number, and CTET tests both the computation and which average to use. The mean (arithmetic average) is the sum of all observations divided by their number — it uses every value, so it is pulled towards extreme values (outliers). The median is the middle value once the data are arranged in order: for an odd count it is the single central value; for an even count it is the average of the two middle values — a step candidates routinely forget, so the data MUST be ordered first. The mode is the value that occurs most often; a set may have one mode, more than one, or none, and it is the only average that works for purely categorical data (most popular colour). The classic CTET pedagogy item: which average is 'best'? When data has extreme outliers (a few very high salaries, one zero score), the median is more representative than the mean. Children's misconceptions worth knowing: thinking the median is just the middle of the unordered list, forgetting to divide by the count for the mean, and confusing mode (most frequent) with the maximum value.

✅ Solved examples

✏️ Practice — try these, take hints as needed

📝 Topic test — 8 questions

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