Mean from a frequency table: Class 9 practice
For a frequency table, mean = Σfx ÷ Σf: multiply each value by its frequency, add, and divide by the total frequency.. Read the method, follow the three worked examples, then try the six questions.
What you should know first
- Multiplication
- Division
The idea behind mean from a frequency table
For a frequency table, mean = Σfx ÷ Σf: multiply each value by its frequency, add, and divide by the total frequency.
Step-by-step method
- Make columns x, f, fx.
- Add the f column and fx column.
- Mean = Σfx ÷ Σf.
Worked example 1 (Basic)
Find the mean: values 13, 23, 32 with frequencies 7, 7, 4.
- Σf = 18
- Σfx = 380
- Mean = 380/18 = 190/9 ≈ 21.11
- Answer: 21.11
Worked example 2 (Standard)
Find the mean: values 13, 22, 31, 40 with frequencies 1, 2, 4, 4.
- Σf = 11
- Σfx = 341
- Mean = 341/11 = 31
- Answer: 31
Worked example 3 (Challenge)
Find the mean: values 11, 23, 32, 41, 53 with frequencies 5, 5, 2, 1, 8.
- Σf = 21
- Σfx = 699
- Mean = 699/21 = 233/7 ≈ 33.29
- Answer: 33.29
Common mistakes and misconceptions
- Dividing by the number of rows instead of Σf
- Forgetting to multiply by f
Practice questions
- (Basic) Find the mean: values 11, 23, 31 with frequencies 2, 1, 7.
- (Basic) Find the mean: values 11, 22, 30 with frequencies 1, 7, 7.
- (Standard) Find the mean: values 10, 20, 33, 40 with frequencies 7, 1, 1, 2.
- (Standard) Find the mean: values 12, 23, 31, 42 with frequencies 6, 2, 5, 4.
- (Challenge) Find the mean: values 10, 21, 33, 43, 52 with frequencies 8, 2, 2, 4, 3.
- (Challenge) Find the mean: values 13, 22, 30, 42, 50 with frequencies 4, 5, 7, 5, 1.
Answer key with full working
- Q1: Σf = 10 → Σfx = 262 → Mean = 262/10 = 131/5 ≈ 26.20 → Answer: 26.20
- Q2: Σf = 15 → Σfx = 375 → Mean = 375/15 = 25 → Answer: 25
- Q3: Σf = 11 → Σfx = 203 → Mean = 203/11 = 203/11 ≈ 18.45 → Answer: 18.45
- Q4: Σf = 17 → Σfx = 441 → Mean = 441/17 = 441/17 ≈ 25.94 → Answer: 25.94
- Q5: Σf = 19 → Σfx = 516 → Mean = 516/19 = 516/19 ≈ 27.16 → Answer: 27.16
- Q6: Σf = 22 → Σfx = 632 → Mean = 632/22 = 316/11 ≈ 28.73 → Answer: 28.73
Syllabus note
This skill is listed under "Statistics" for Class 9 in the NCERT/CBSE books. ICSE, IGCSE, IB and state boards may teach it in a different chapter or year.
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.
Related practice and notes
Frequently asked questions
Which chapter is mean from a frequency table in?
"Statistics", Class 9 Maths (NCERT/CBSE). Other boards may place it differently.
How were the answers checked?
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.