Median and Mode of Grouped Data
Learning to calculate the median and mode of data organised into class intervals.
Core concept
These formulas allow precise estimation of the median and mode even when working with grouped (rather than individual) data, where the exact original values are unknown, only which class interval they fall into. Understanding when to use mean, median, or mode for grouped data depends on the nature of the data and what kind of 'typical value' is most meaningful or useful for the specific real-world context being analysed.
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Quick notes
• The median class is where cumulative frequency first exceeds n/2 (n = total frequency).
• The mode is estimated from the modal class (the interval with highest frequency).
• Specific formulas use class boundaries, frequencies, and class width to estimate median/mode.
• These formulas work even with grouped data, where individual exact values are unknown.