Class 11 Applied Mathematics Chapter 10 Descriptive Statistics NCERT Book PDF gives students the official chapter text for data types, graph choice, averages, measures of dispersion, skewness, kurtosis, percentile rank and correlation. The PDF follows the 2026-27 NCERT chapter and helps students revise statistics with the original examples beside them.
- Official source: download the original NCERT chapter PDF with theory, examples, activities and practice questions.
- Exam value: Descriptive Statistics supports data interpretation, survey analysis and business decision questions.
- Best for practice: read this PDF before solving questions on averages, spread and correlation.
This chapter PDF is the reference text students should keep open while revising graph choice, centre values and spread measures.
Student Feedback: In a Collegedunia poll of more than 12,000 students before the 2026 boards, most students said Descriptive Statistics became easier after separating graph choice, average choice and spread choice into three steps.
Descriptive Statistics NCERT Book PDF for Class 11 Applied Mathematics
The NCERT Book PDF is the base text for this Descriptive Statistics chapter. It explains how raw data is organised, represented, summarised and interpreted through numerical measures.
| Chapter part | What students read in the PDF | Why it matters |
|---|---|---|
| Data and scales | Primary, secondary, nominal, ordinal, interval and ratio data | Builds the base for valid comparison |
| Graphs | Bar chart, pie chart, line graph, histogram and frequency polygon | Helps students present data correctly |
| Central tendency | Mean, median and mode | Summarises a data set with one centre value |
| Dispersion and relation | Range, quartile deviation, mean deviation, standard deviation and correlation | Explains spread and association between variables |
Data Types and Graph Choice in Descriptive Statistics
Descriptive Statistics starts with identifying the type of data. Qualitative data uses categories, while quantitative data uses numbers that can be counted, measured and compared.
- Nominal data: category names with no natural order.
- Ordinal data: categories that can be ranked.
- Interval data: numerical values with equal gaps but no true zero.
- Ratio data: numerical values with equal gaps and a true zero.
Graph choice should happen after the data type is clear, not before it. A bar chart compares categories, a pie chart shows parts of a whole, a histogram groups continuous values and a frequency polygon helps compare distributions.
Descriptive Statistics Measures of Dispersion Video
Source: Magnet Brains on YouTube
Mean Median Mode and Measures of Spread
The three averages answer different questions. Mean uses every observation, median gives the middle position and mode gives the most frequent value. In a skewed distribution, the median often gives a more stable summary than the mean.
| Measure | Formula idea | Use it when |
|---|---|---|
| Range | Largest value minus smallest value | A quick spread estimate is enough |
| Quartile deviation | Half of Q3 minus Q1 | The middle 50 percent matters most |
| Mean deviation | Average absolute distance from a centre | Distances from mean or median are needed |
| Standard deviation | Square root of variance | A complete spread measure is needed |
Skewness Kurtosis Percentile Rank and Correlation
Skewness tells whether the data has a longer tail on one side. A positive skew has a longer right tail, while a negative skew has a longer left tail. Kurtosis describes whether the data is sharply peaked or flatter than a normal pattern.
Percentile rank compares one value with the rest of the data. Correlation checks how two variables move together. A positive correlation means both variables tend to move in the same direction, while a negative correlation means one increases as the other decreases.
| Concept | What to remember | Common mistake |
|---|---|---|
| Skewness | Mean, median and mode shift when the tail is long | Calling every unequal distribution skewed without checking direction |
| Kurtosis | Compare peak and tail behaviour | Using it as a measure of average |
| Percentile rank | Counts how many values lie below a score | Confusing percentile with percentage marks |
| Correlation | Coefficient lies between -1 and +1 | Reading correlation as causation |
How to Use the Class 11 Applied Mathematics Descriptive Statistics PDF
The PDF works best when students read the examples before attempting questions. Statistics questions reward interpretation, so the final answer should explain what the calculated value means.
| Study pass | What to do | Target |
|---|---|---|
| Pass 1 | Read data type and graph selection pages | Choose the right representation |
| Pass 2 | Copy formulas for centre and spread with one example each | Separate average from variation |
| Pass 3 | Solve NCERT examples before exercise questions | Improve steps and notation |
| Pass 4 | Write one interpretation sentence after each calculation | Connect numbers to data meaning |
Quick tip: Do not calculate the mean before checking whether extreme values are present. If the data has outliers, compare the median as well.
Related Class 11 Applied Mathematics Resources for Descriptive Statistics
Also Check: use the original book PDF with the matching notes, solutions and handwritten notes for the same chapter.
| Resource | Best used for | Link |
|---|---|---|
| NCERT Notes | Typed explanation and formula tables | Descriptive Statistics Class 11 Notes |
| NCERT Solutions | Step-by-step answers to textbook questions | Descriptive Statistics Class 11 NCERT Solutions |
| Handwritten Notes | Quick visual recall before practice | Descriptive Statistics Class 11 Handwritten Notes |
Class 11 Applied Mathematics NCERT Book PDFs for All Chapters
Related Links: download neighbouring NCERT Book PDFs in the same Applied Mathematics format.
| Chapter | Class 11 Applied Mathematics NCERT Book PDF |
|---|---|
| Chapter 6 | Permutations and Combinations Class 11 NCERT Book PDF |
| Chapter 7 | Mathematical and Logical Reasoning Class 11 NCERT Book PDF |
| Chapter 8 | Calculus Class 11 NCERT Book PDF |
| Chapter 9 | Probability Class 11 NCERT Book PDF |
| Chapter 10 | Descriptive Statistics Class 11 NCERT Book PDF |
Descriptive Statistics Class 11 Applied Mathematics NCERT Book PDF FAQs
Ques. What does the Descriptive Statistics NCERT Book PDF contain?
Ans. It contains the official NCERT chapter text, examples and exercises on data types, graphs, averages, dispersion, skewness, kurtosis, percentile rank and correlation.
Ques. Is this Class 11 Applied Mathematics Chapter 10 PDF useful for 2026-27 exams?
Ans. Yes. The PDF follows the 2026-27 Applied Mathematics syllabus and helps students revise descriptive statistics from the official chapter.
Ques. Which spread measures are important in Descriptive Statistics?
Ans. Range, quartile deviation, mean deviation, variance and standard deviation are important spread measures in this chapter.
Ques. How should students use this NCERT Book PDF?
Ans. Read the definitions first, match graphs with data types, then solve NCERT examples before attempting the exercise questions.
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