CBSE Class 10 Mathematics Standard 2024: question 37
Set in the CBSE Class 10 board exam of 2024, paper 30/3/1, section E, question 37, for 4 marks. Try it first; the hints and our step-by-step solution are below.
Q37 · 4 marks · Case-basedCompetency-basedStatistics
Vocational training complements traditional education by providing practical skills and hands-on experience. While education equips individuals with a broad knowledge base, vocational training focuses on job-specific skills, enhancing employability thus making the student self-reliant. Keeping this in view, a teacher made the following table giving the frequency distribution of students/adults undergoing vocational training from the training institute.
| Age (in years) | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 | 50-54 |
|---|---|---|---|---|---|---|---|---|
| Number of participants | 62 | 132 | 96 | 37 | 13 | 11 | 10 | 4 |
From the above answer the following questions:
- (i)1 mark
What is the lower limit of the modal class of the above data?
- (ii)2 marks
(a) Find the median class of the above data.
OR
(ii)2 marks(b) Find the number of participants of age less than 50 years who undergo vocational training.
- (iii)1 mark
Give the empirical relationship between mean, median and mode.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 30/3/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
The modal class is the class with the largest frequency. The classes have gaps, so make them continuous first.
Hint 2
For the median class, find n/2 and look for the first cumulative frequency that exceeds it.
Hint 3
Less than 50 years means every class except 50–54.
Step-by-step solution
Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.
- 1 mark
(i) The highest frequency is 132, which belongs to the class 20–24. Make the classes continuous by subtracting 0.5 from each lower limit and adding 0.5 to each upper limit. The modal class becomes 19.5–24.5, so its lower limit is 19.5.
- 1 mark
(ii)(a) Cumulative frequency table, using continuous classes:
Age 14.5–19.5 19.5–24.5 24.5–29.5 29.5–34.5 34.5–39.5 39.5–44.5 44.5–49.5 49.5–54.5 f 62 132 96 37 13 11 10 4 cf 62 194 290 327 340 351 361 365 - ½ mark
(ii)(a) Here , so .
- ½ mark
(ii)(a) The first cumulative frequency greater than 182.5 is 194. So the median class is 19.5–24.5 (that is, 20–24).
- 2 marks
(ii)(b) Participants younger than 50 years are those in all classes up to 45–49. Their number . (Equivalently, .)
- 1 mark
(iii) Empirical relationship:
Answer: (i) 19.5; (ii)(a) 19.5–24.5, (ii)(b) 361; (iii) 3 Median = Mode + 2 Mean
Where the marks are
- (i) Identifies the modal class 19.5–24.5 with lower limit 19.5 (1 mark)
- (ii)(a) Correct cumulative frequency table (1 mark), n/2 = 182.5 (½ mark), median class 19.5–24.5 (½ mark)
- (ii)(b) Adds the frequencies of the classes below 50 to get 361 (2 marks)
- (iii) States 3 Median = Mode + 2 Mean (1 mark)
Revise the chapter
- Chapter: Statistics (notes, formulas, where marks are lost and every past question)
- Topic: Median of Grouped Data
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The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.