Statistics
Kerala Board · Class 9 · Mathematics
Flashcards for Statistics — Kerala Board Class 9 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.
Find the mean of the marks: 25, 34, 42, 20, 39, 50, 28, 30, 50, 11, 20, 42, 45, 40, 7
Answer
Step 1: Add all observations: 25+34+42+20+39+50+28+30+50+11+20+42+45+40+7 = 483 Step 2: Count observations: n = 15 Step 3: Apply formula Mean = Σx/n = 483/15 = 32.2 Answer: 32.2 marks
The weights (kg) of 6 students are: 45, 48, 52, 46, 45, 50. Find the median weight.
Answer
Step 1: Arrange in ascending order: 45, 45, 46, 48, 50, 52 Step 2: n = 6 (even number) Step 3: Median = average of (n/2)th and (n/2 + 1)th terms Step 4: Median = average of 3rd and 4th terms = (46 + 4
Find the mode of shoe sizes sold: 7, 8, 6, 7, 9, 8, 7, 6, 8, 7, 5, 7
Answer
Step 1: Count frequency of each size: Size 5: 1 time, Size 6: 2 times, Size 7: 5 times, Size 8: 3 times, Size 9: 1 time Step 2: Identify highest frequency: Size 7 appears 5 times (maximum) Step 3: Mod
Find the mean using frequency table: Marks: 10, 20, 30, 40, 50 Students: 5, 8, 12, 10, 5
Answer
Step 1: Use formula x̄ = Σfixi/Σfi Step 2: Calculate fixi for each class: 10×5=50, 20×8=160, 30×12=360, 40×10=400, 50×5=250 Step 3: Σfixi = 50+160+360+400+250 = 1220 Step 4: Σfi = 5+8+12+10+5 = 40 Ste
If mean of 8, 12, 16, x, 20, 24 is 16, find x.
Answer
Step 1: Use Mean = Σx/n Step 2: 16 = (8+12+16+x+20+24)/6 Step 3: 16 = (80+x)/6 Step 4: 96 = 80+x Step 5: x = 96-80 = 16 Verification: (8+12+16+16+20+24)/6 = 96/6 = 16 ✓ Answer: x = 16
Find median from frequency table: Value: 2, 4, 6, 8, 10 Frequency: 3, 5, 7, 4, 1
Answer
Step 1: Find cumulative frequencies: Value: 2, 4, 6, 8, 10 CF: 3, 8, 15, 19, 20 Step 2: n = 20 (even), so find average of 10th and 11th observations Step 3: Both 10th and 11th observations fall in val
Using deviation method, find mean if A = 25: Values: 20, 22, 24, 26, 28 Frequencies: 4, 6, 8, 10, 2
Answer
Step 1: Calculate deviations di = xi - A d = -5, -3, -1, 1, 3 Step 2: Calculate fidi: 4×(-5)=-20, 6×(-3)=-18, 8×(-1)=-8, 10×1=10, 2×3=6 Step 3: Σfidi = -20-18-8+10+6 = -30 Step 4: Σfi = 4+6+8+10+2 = 3
Find range and class intervals for data: 15, 23, 67, 45, 88, 92, 34, 78, 56, 41
Answer
Step 1: Find maximum and minimum values Max = 92, Min = 15 Step 2: Range = Max - Min = 92 - 15 = 77 Step 3: For convenient class intervals with width 10: Classes: 15-24, 25-34, 35-44, 45-54, 55-64, 65
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What are the important topics in Statistics for Kerala Board Class 9 Mathematics?
Statistics covers several key topics that are frequently asked in Kerala Board Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.
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Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.
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There are 20 flashcards for Statistics covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.
Sources & Official References
- Kerala Board of Public Examinations — keralapareekshabhavan.in
- National Education Policy 2020 — education.gov.in
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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