Skip to main content
Super TutorResources
Chapter 19 of 28
Chapter Summary

Mean and Median — Chapter Summary

ICSE · Class 9 · Mathematics

Summary of Mean and Median for ICSE Class 9 Mathematics. Key concepts: Mean is the sum of all, Σxi means the sum of all and The sum of deviations of all.

41 questions22 flashcards15 formulas & key relations5 concepts

Interactive on Super Tutor

Studying Mean and Median? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for chapter summary and more.

Try Super Tutor — Free

Free trial, no card needed.

An illustration showing the formula for calculating the mean of ungrouped data, with an example set of numbers and their sum and count.
Super Tutor

One of 4 illustrations for Mean and Median in Super Tutor — alongside flashcards, concept maps and practice questions.

Overview

Mean and median are measures used to describe a set of ungrouped data. Mean gives the average value of the data, while median gives the middle value after arranging the data in order. Mean is found by adding all observations and dividing by the number of observations. Median depends on the position

Key Concepts

Mean is the sum of all

Mean is the sum of all observations divided by the total number of observations. It is also called arithmetic mean or average. For n observations x1,

Σxi means the sum of all

Σxi means the sum of all observations x1, x2, x3, ..., xn. It is a short way of writing the total of all values used in mean calculation.

The sum of deviations of all

The sum of deviations of all observations from their mean is zero: Σ(x−x̄)=0.

If each observation is increased by

If each observation is increased by a quantity a, then the mean also increases by a. Mean of x1+a, x2+a, ..., xn+a = x̄+a.

If each observation is decreased by

If each observation is decreased by a quantity a, then the mean also decreases by a. Mean of x1−a, x2−a, ..., xn−a = x̄−a.

Learning Objectives

  • Understand the meaning of mean and median for ungrouped data
  • Use the formula for mean of n observations
  • Apply the properties of mean when all observations are increased, decreased, multiplied, or divided by the same number
  • Find the median of data sets with odd and even numbers of observations
  • Solve simple problems involving correction of a wrong observation in mean

Frequently Asked Questions

What are the important topics in Mean and Median for ICSE Class 9 Mathematics?
Key topics in Mean and Median include Mean of Ungrouped Data, Properties of Mean, Mean: Solved Examples and Short Questions, Median of Ungrouped Data. Study these first, then practise questions on each for Class 9 exams.
How should I revise Mean and Median for Class 9 exams?
Learn the core ideas first, then work through the 41 practice questions on Mean and Median. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Mean and Median

All ICSE Class 9 Mathematics Chapter Summary

For serious students

Get the full Mean and Median chapter — start free.

Quizzes, flashcards, an AI doubt solver and a study plan for ICSE Class 9 Mathematics. Free to start, no card needed.

Try Super Tutor Free
Try this chapter free