Mean of grouped data
The mean of grouped data is the average value found by using class marks and frequencies of the grouped table.
Practice This ConceptMain explanation
Teacher explanation
For grouped data, we do not use every original value separately. We first take the class mark of each class interval, multiply it by the frequency, add all such products, and divide by total frequency. This gives a single representative average for the whole data set.
Example
If class marks are 10, 20, and 30 with frequencies 2, 3, and 5, then mean = (2x10 + 3x20 + 5x30) / 10 = 23.
Simple analogy
Think: class mark first, frequency next, then divide at the end.
Common confusion
Students often use class intervals directly instead of class marks, which gives an incorrect mean.
Exam tip
Always write the class mark first, then multiply by frequency, and keep the total frequency in the denominator.
Answer writing and exam use
1-mark use
Write the exact meaning of mean of grouped data in one clean line.
2-mark use
Define mean of grouped data and add one example or condition.
3-mark use
Explain mean of grouped data, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
Help improve this page
Found something confusing, incorrect, or missing?