Chapter: Statistics
Goal of this chapter: By the end of this lesson, you will feel confident with the key NDA-level concepts of Chapter: Statistics and be able to solve exam-style questions on your own.
हिंदी Note: इस chapter को आराम से पढ़िए – examples और छोटे-छोटे अभ्यास के साथ। एक बार समझ आ गया तो NDA में Chapter: Statistics के सवाल आपके लिए बहुत आसान हो जाएंगे 😄
Why is this important?
Statistics plays an important role in NDA exams, especially in the Maths section. Understanding mean, median, mode, and range is essential for data interpretation and practical mathematics. Questions from this chapter are often direct and scoring.
Tips & Formulas
- Mean (Average): Sum of observations / Number of observations
- Median: Middle term when data is arranged in ascending order
- Mode: Most frequent observation
- Range: Difference between highest and lowest values
Practice Questions with Hints
Extra Practice Questions (Answers Only)
- Find the mean of: 12, 15, 20, 25 → 18
- Find the mode: 7, 8, 9, 7, 10, 7, 6 → 7
- Median of: 21, 23, 20, 25, 22 → 22
- Range of: 14, 22, 18, 27 → 13
- Sum of 6 numbers with average 12 → 72
- If mean of x, x+2, x+4 is 20 → x = 18
Quick Recap | सार
Now you should be able to:
- Recall the key ideas of this chapter without looking at the book.
- Solve most NDA-style questions of this topic step by step.
- Identify and avoid the most common traps used in competitive exams.
Self-check: अगर practice questions अपने आप हो रहे हैं, तो chapter strong है। जो सवाल अटकते हैं, बस उन्हें दोबारा देख लें।
Common Exam Mistakes | आम गलतियाँ
- जल्दी-जल्दी में question पूरा पढ़े बिना solve करना।
- Sign (+/−) या power गलत लिख देना।
- Last step में calculation check न करना – आधा काम सही, answer गलत।
ध्यान रखिए: NDA में topper वो नहीं जो सब कुछ जानता है, बल्कि वो है जो छोटी-छोटी गलतियाँ avoid कर देता है।