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Statistics
Statistics in Class 10 focuses on organising data, finding measures of central tendency, and interpreting results clearly. Students must know how to handle grouped data, because board questions often give class intervals and frequency tables instead of raw values. This chapter also connects calculation with reading tables and graphs. A good answer should show the correct formula, the correct class, the correct cumulative frequency, and the correct interpretation, especially for mean, median, mode, and ogives.
Difficulty
Medium
Study time
96-120 min
Plan by time
Pick the window that matches what you have right now.
If you have 15 min
Last-pass revision
Skim the Quick Revision table — definitions, formulas, and the traps board examiners reuse.
Open Quick RevisionIf you have 45 min
Targeted practice
Read the high-priority concepts, then take the chapter MCQ quiz to find weak spots.
Start MCQ QuizIf you have 96 min
First full pass
Walk every concept in chapter order, then revise and quiz. Best for the first time you study this chapter.
Open Key ConceptsChapter Learning Map
Start with one of the buckets below, then open the full map when you want the complete concept roadmap.
Key Concepts
Concepts grouped the way the chapter is taught — open the bucket that matches what you want to revise.
Core Concepts
high priorityOpen the chapter concepts in a clean revision order.
Mean of grouped data
The mean of grouped data is the average value found by using class marks and frequencies of the grouped table.
Assumed mean method
The assumed mean method is a shortcut for finding the mean of grouped data by taking one convenient central value as a reference.
Step deviation method
The step deviation method is a fast way to find the mean of grouped data when class widths are equal.
Median of grouped data
The median of grouped data is the middle value that divides the frequency distribution into two equal parts.
Modal class
The modal class is the class interval with the highest frequency in grouped data.
Mode of grouped data
The mode of grouped data is the value that occurs most frequently, estimated using the modal class and a standard formula.
Cumulative frequency
Cumulative frequency is the running total of frequencies up to a class interval.
Less-than cumulative frequency table
A less-than cumulative frequency table lists the number of observations less than each upper class boundary.
Ogive interpretation
An ogive is a cumulative frequency graph used to interpret grouped data and locate values such as the median.
Median from ogive
The median from an ogive is found by using the total frequency, locating N/2 on the cumulative frequency axis, and reading the corresponding class boundary value.
Choice of class mark
The class mark is the midpoint of a class interval and is used as the representative value of that class in grouped-data calculations.
Comparing central tendency measures
Comparing central tendency measures means deciding whether mean, median, or mode best describes a data set for a given situation.
Exam Intelligence
Use this section to decide what deserves the most revision time.
High Probability Topics
- Mean of grouped data
- Assumed mean method
- Step deviation method
- Median of grouped data
- Modal class
- Mode of grouped data
- Cumulative frequency
- Less-than cumulative frequency table
Common Traps
- Using class limits instead of class marks in mean calculations.
- Forgetting to add the assumed mean back after using the shortcut method.
- Using the modal class as the mode itself in grouped data.
- Writing cumulative frequency as repeated frequency instead of running total.
- Using ordinary frequency points on an ogive instead of cumulative frequencies.
- Choosing mean automatically when the data has extreme values.
Likely Question Types
- MCQ: concept checks, applications, and common mistakes
- Very short answer: definitions, formulas, or conditions
- Short answer: worked method, example, or reason-based explanation
- Case-based: chapter scenario with concept-linked subparts
Quick Revision
Concept, formula or equation to remember, and the trap that loses marks — in one scannable view.
- Grouped data needs class marks, frequencies, and careful formulas.
- Mean is the average, median is the middle position, and mode is the most frequent value.
- Cumulative frequency supports median and ogive work.
- Assumed mean and step deviation save time in long tables.
- Ogive reading uses N/2 and graph interpretation, not ordinary frequency.
- Mean of grouped data: The mean of grouped data is the average value found by using class marks and frequencies of the grouped table.
- Assumed mean method: The assumed mean method is a shortcut for finding the mean of grouped data by taking one convenient central value as a reference.
- Step deviation method: The step deviation method is a fast way to find the mean of grouped data when class widths are equal.
Practice
Use short concept checks first, then move into the full chapter test.
Free Chapter MCQ Quiz
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