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By Ankit Gupta
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Updated on 22 Jul 2026, 15:25 IST
NCERT Solutions for Class 10 Maths Chapter 13 Statistics 2026-27 help students understand how to collect, organize, study, and interpret data in an easy way. Statistics is an important chapter in Class 10 Maths because it teaches students how to find useful information from numbers. In this chapter, students learn about grouped data, mean, median, and mode. They also understand how these concepts are used in real-life situations, such as comparing marks, studying population data, checking sales records, and analysing survey results.
The NCERT Solutions for Class 10 Maths Chapter 13 Statistics 2026-27 are prepared according to the latest NCERT syllabus and exam pattern. Each question is explained step by step so that students can understand the method clearly and avoid common mistakes. These solutions also help learners revise formulas, improve calculation skills, and prepare better for school exams and board exams.
Infinity Learn provides clear and student-friendly NCERT solutions that make difficult topics easier to understand. With the help of Infinity Learn, students can practice all important questions from Chapter 13 and build confidence in solving problems based on mean, median, and mode. The explanations are written in simple language, making them useful for quick learning and revision.
Using NCERT Solutions for Class 10 Maths Chapter 13 Statistics 2026-27 regularly can help students strengthen their basic concepts and improve accuracy. These solutions are also helpful for homework, class tests, assignments, and exam preparation. By studying the solved examples and practising similar questions, students can understand the chapter in a better way.
Students can download NCERT Solutions for Class 10 Maths Chapter 13 Statistics PDF to study the chapter easily anytime and anywhere. The PDF contains clear, step-by-step solutions to all the NCERT exercise questions based on mean, median, and mode. It is useful for completing homework, revising important formulas, and preparing for school and board exams.
Question 1: A group of students recorded the number of plants grown in 20 houses as part of an environmental awareness programme. Find the mean number of plants per house.
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| Number of plants | 0-2 | 2-4 | 4-6 | 6-8 | 8-10 | 10-12 | 12-14 |
| Number of houses | 1 | 2 | 1 | 5 | 6 | 2 | 3 |
Solution:
The class marks and frequencies are small, so the direct method is convenient.
Class mark, xi = (Lower class limit + Upper class limit)/2
Mean = (Σfixi)/(Σfi)

| Class interval | Frequency, fi | Class mark, xi | fixi |
| 0-2 | 1 | 1 | 1 × 1 = 1 |
| 2-4 | 2 | 3 | 2 × 3 = 6 |
| 4-6 | 1 | 5 | 1 × 5 = 5 |
| 6-8 | 5 | 7 | 5 × 7 = 35 |
| 8-10 | 6 | 9 | 6 × 9 = 54 |
| 10-12 | 2 | 11 | 2 × 11 = 22 |
| 12-14 | 3 | 13 | 3 × 13 = 39 |
| Total | 20 | 162 |
Mean = 162/20
Mean = 8.1

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Answer: The mean number of plants per house is 8.1. The direct method is used because the class marks and frequencies are easy to multiply.
Question 2: The following distribution represents the daily wages of 50 factory workers. Find their mean daily wage using a suitable method.
| Daily wage in Rs. | 100-120 | 120-140 | 140-160 | 160-180 | 180-200 |
| Number of workers | 12 | 14 | 8 | 6 | 10 |
Solution:
Since all class intervals have the same width, the step-deviation method is suitable.

Take the assumed mean, a = 150, and class size, h = 20.
ui = (xi - a)/h
Mean = a + [(Σfiui)/(Σfi)] × h
| Daily wage | fi | xi | di = xi - 150 | ui = di/20 | fiui |
| 100-120 | 12 | 110 | -40 | -2 | -24 |
| 120-140 | 14 | 130 | -20 | -1 | -14 |
| 140-160 | 8 | 150 | 0 | 0 | 0 |
| 160-180 | 6 | 170 | 20 | 1 | 6 |
| 180-200 | 10 | 190 | 40 | 2 | 20 |
| Total | 50 | -12 |
Mean = 150 + [(-12)/50] × 20
= 150 - 4.8
= 145.2
Answer: The mean daily wage is Rs. 145.20.
Question 3: The following distribution gives the daily pocket allowance of children in a locality. The mean pocket allowance is Rs. 18. Find the missing frequency f.
| Pocket allowance in Rs. | 11-13 | 13-15 | 15-17 | 17-19 | 19-21 | 21-23 | 23-25 |
| Number of children | 7 | 6 | 9 | 13 | f | 5 | 4 |
Solution:
Take the assumed mean a = 18.
Using the assumed-mean formula:
Mean = a + (Σfidi)/(Σfi)
| Class interval | fi | xi | di = xi - 18 | fidi |
| 11-13 | 7 | 12 | -6 | -42 |
| 13-15 | 6 | 14 | -4 | -24 |
| 15-17 | 9 | 16 | -2 | -18 |
| 17-19 | 13 | 18 | 0 | 0 |
| 19-21 | f | 20 | 2 | 2f |
| 21-23 | 5 | 22 | 4 | 20 |
| 23-25 | 4 | 24 | 6 | 24 |
| Total | 44 + f | 2f - 40 |
The given mean is 18.
18 = 18 + (2f - 40)/(44 + f)
Therefore, (2f - 40)/(44 + f) = 0
2f - 40 = 0
2f = 40
f = 20
Answer: The missing frequency is 20.
Question 4: The heartbeats per minute of 30 women were recorded in a hospital. Find the mean number of heartbeats per minute.
| Heartbeats per minute | 65-68 | 68-71 | 71-74 | 74-77 | 77-80 | 80-83 | 83-86 |
| Number of women | 2 | 4 | 3 | 8 | 7 | 4 | 2 |
Solution:
Use the step-deviation method with assumed mean a = 75.5 and class size h = 3.
| Class interval | fi | xi | di = xi - 75.5 | ui = di/3 | fiui |
| 65-68 | 2 | 66.5 | -9 | -3 | -6 |
| 68-71 | 4 | 69.5 | -6 | -2 | -8 |
| 71-74 | 3 | 72.5 | -3 | -1 | -3 |
| 74-77 | 8 | 75.5 | 0 | 0 | 0 |
| 77-80 | 7 | 78.5 | 3 | 1 | 7 |
| 80-83 | 4 | 81.5 | 6 | 2 | 8 |
| 83-86 | 2 | 84.5 | 9 | 3 | 6 |
| Total | 30 | 4 |
Mean = 75.5 + (4/30) × 3
= 75.5 + 0.4
= 75.9
Answer: The mean is 75.9 heartbeats per minute.
Question 5: Mangoes are packed in boxes in the following manner. Find the mean number of mangoes in a box. Also state the method used.
| Number of mangoes | 50-52 | 53-55 | 56-58 | 59-61 | 62-64 |
| Number of boxes | 15 | 110 | 135 | 115 | 25 |
Solution:
The intervals are inclusive. They may be written as continuous intervals by subtracting 0.5 from every lower limit and adding 0.5 to every upper limit.
Take a = 57 and h = 3.
| Continuous interval | fi | xi | ui = (xi - 57)/3 | fiui |
| 49.5-52.5 | 15 | 51 | -2 | -30 |
| 52.5-55.5 | 110 | 54 | -1 | -110 |
| 55.5-58.5 | 135 | 57 | 0 | 0 |
| 58.5-61.5 | 115 | 60 | 1 | 115 |
| 61.5-64.5 | 25 | 63 | 2 | 50 |
| Total | 400 | 25 |
Mean = 57 + (25/400) × 3
= 57 + 0.1875
= 57.1875
Answer: The mean number of mangoes per box is 57.1875. The step-deviation method is convenient because the frequencies are large and the class marks have a common difference.
Question 6:The daily expenditure on food of 25 households is shown below. Find the mean daily expenditure.
| Daily expenditure in Rs. | 100-150 | 150-200 | 200-250 | 250-300 | 300-350 |
| Number of households | 4 | 5 | 12 | 2 | 2 |
Solution:
Take assumed mean a = 225 and class size h = 50.
| Expenditure | fi | xi | ui = (xi - 225)/50 | fiui |
| 100-150 | 4 | 125 | -2 | -8 |
| 150-200 | 5 | 175 | -1 | -5 |
| 200-250 | 12 | 225 | 0 | 0 |
| 250-300 | 2 | 275 | 1 | 2 |
| 300-350 | 2 | 325 | 2 | 4 |
| Total | 25 | -7 |
Mean = 225 + [(-7)/25] × 50
= 225 - 14
= 211
Answer: The mean daily expenditure on food is Rs. 211.
Question 7: The concentration of SO2 in the air was measured in 30 localities. Find the mean concentration.
| SO2 concentration in ppm | Frequency |
| 0.00-0.04 | 4 |
| 0.04-0.08 | 9 |
| 0.08-0.12 | 9 |
| 0.12-0.16 | 2 |
| 0.16-0.20 | 4 |
| 0.20-0.24 | 2 |
Solution:
Take a = 0.14 and h = 0.04.
| Class interval | fi | xi | ui = (xi - 0.14)/0.04 | fiui |
| 0.00-0.04 | 4 | 0.02 | -3 | -12 |
| 0.04-0.08 | 9 | 0.06 | -2 | -18 |
| 0.08-0.12 | 9 | 0.10 | -1 | -9 |
| 0.12-0.16 | 2 | 0.14 | 0 | 0 |
| 0.16-0.20 | 4 | 0.18 | 1 | 4 |
| 0.20-0.24 | 2 | 0.22 | 2 | 4 |
| Total | 30 | -31 |
Mean = 0.14 + [(-31)/30] × 0.04
= 0.14 - 0.04133
= 0.09867 ppm
Rounded to three decimal places, the mean is 0.099 ppm.
Answer: The mean concentration of SO2 is approximately 0.099 ppm.
Question 8: The following table records the number of days for which 40 students were absent during a term. Find the mean number of absent days.
| Number of days | 0-6 | 6-10 | 10-14 | 14-20 | 20-28 | 28-38 | 38-40 |
| Number of students | 11 | 10 | 7 | 4 | 4 | 3 | 1 |
Solution:
The class widths are not equal, so use the assumed-mean method. Take a = 17.
| Number of days | fi | xi | di = xi - 17 | fidi |
| 0-6 | 11 | 3 | -14 | -154 |
| 6-10 | 10 | 8 | -9 | -90 |
| 10-14 | 7 | 12 | -5 | -35 |
| 14-20 | 4 | 17 | 0 | 0 |
| 20-28 | 4 | 24 | 7 | 28 |
| 28-38 | 3 | 33 | 16 | 48 |
| 38-40 | 1 | 39 | 22 | 22 |
| Total | 40 | -181 |
Mean = 17 + (-181/40)
= 17 - 4.525
= 12.475
Answer: The mean number of absent days is approximately 12.48 days.
Question 9: The following table gives the literacy rates of 35 cities. Find the mean literacy rate.
| Literacy rate in percent | 45-55 | 55-65 | 65-75 | 75-85 | 85-95 |
| Number of cities | 3 | 10 | 11 | 8 | 3 |
Solution:
Take a = 70 and h = 10.
| Literacy rate | fi | xi | ui = (xi - 70)/10 | fiui |
| 45-55 | 3 | 50 | -2 | -6 |
| 55-65 | 10 | 60 | -1 | -10 |
| 65-75 | 11 | 70 | 0 | 0 |
| 75-85 | 8 | 80 | 1 | 8 |
| 85-95 | 3 | 90 | 2 | 6 |
| Total | 35 | -2 |
Mean = 70 + (-2/35) × 10
= 70 - 20/35
= 69.4286
Answer: The mean literacy rate is approximately 69.43%.
Question 1: The ages of patients admitted to a hospital during one year are given below. Find the mean and mode. Compare and interpret the results.
| Age in years | 5-15 | 15-25 | 25-35 | 35-45 | 45-55 | 55-65 |
| Number of patients | 6 | 11 | 21 | 23 | 14 | 5 |
Mean:
Take a = 30 and di = xi - 30.
| Age | fi | xi | di | fidi |
| 5-15 | 6 | 10 | -20 | -120 |
| 15-25 | 11 | 20 | -10 | -110 |
| 25-35 | 21 | 30 | 0 | 0 |
| 35-45 | 23 | 40 | 10 | 230 |
| 45-55 | 14 | 50 | 20 | 280 |
| 55-65 | 5 | 60 | 30 | 150 |
| Total | 80 | 430 |
Mean = 30 + 430/80
= 30 + 5.375
= 35.375 years
Therefore, mean age = 35.38 years, approximately.
Mode:
The highest frequency is 23, so the modal class is 35-45.
Mode = l + [(f1 - f0)/(2f1 - f0 - f2)] × h
Here, l = 35, f1 = 23, f0 = 21, f2 = 14 and h = 10.
Mode = 35 + [(23 - 21)/(46 - 21 - 14)] × 10
= 35 + (2/11) × 10
= 36.82 years, approximately.
Answer: The mean age is approximately 35.38 years, while the modal age is approximately 36.82 years. Thus, the average patient was about 35 years old, while the largest concentration of patients was around 37 years old.
Question 2: The lifetimes of 225 electrical components are given below. Determine their modal lifetime.
| Lifetime in hours | 0-20 | 20-40 | 40-60 | 60-80 | 80-100 | 100-120 |
| Frequency | 10 | 35 | 52 | 61 | 38 | 29 |
Solution:
The highest frequency is 61, so the modal class is 60-80.
Here, l = 60, h = 20, f1 = 61, f0 = 52 and f2 = 38.
Mode = 60 + [(61 - 52)/(2 × 61 - 52 - 38)] × 20
= 60 + (9/32) × 20
= 60 + 5.625
= 65.625 hours
Answer: The modal lifetime of the components is 65.625 hours.
Question 3: The monthly expenditure of 200 families is given below. Find the modal and mean monthly expenditure.
| Monthly expenditure in Rs. | Number of families |
| 1000-1500 | 24 |
| 1500-2000 | 40 |
| 2000-2500 | 33 |
| 2500-3000 | 28 |
| 3000-3500 | 30 |
| 3500-4000 | 22 |
| 4000-4500 | 16 |
| 4500-5000 | 7 |
Mode:
The highest frequency is 40, so the modal class is 1500-2000.
Here, l = 1500, f1 = 40, f0 = 24, f2 = 33 and h = 500.
Mode = 1500 + [(40 - 24)/(80 - 24 - 33)] × 500
= 1500 + (16/23) × 500
= 1500 + 347.826
= Rs. 1847.83, approximately.
Mean:
Take a = 2750 and h = 500.
| Expenditure | fi | xi | ui | fiui |
| 1000-1500 | 24 | 1250 | -3 | -72 |
| 1500-2000 | 40 | 1750 | -2 | -80 |
| 2000-2500 | 33 | 2250 | -1 | -33 |
| 2500-3000 | 28 | 2750 | 0 | 0 |
| 3000-3500 | 30 | 3250 | 1 | 30 |
| 3500-4000 | 22 | 3750 | 2 | 44 |
| 4000-4500 | 16 | 4250 | 3 | 48 |
| 4500-5000 | 7 | 4750 | 4 | 28 |
| Total | 200 | -35 |
Mean = 2750 + (-35/200) × 500
= 2750 - 87.5
= Rs. 2662.50
Answer: The modal monthly expenditure is approximately Rs. 1847.83, and the mean monthly expenditure is Rs. 2662.50.
Question 4: The state-wise teacher-student ratios in higher secondary schools are shown below. Find the mean and mode, and interpret the results.
| Students per teacher | Number of states or U.T.s |
| 15-20 | 3 |
| 20-25 | 8 |
| 25-30 | 9 |
| 30-35 | 10 |
| 35-40 | 3 |
| 40-45 | 0 |
| 45-50 | 0 |
| 50-55 | 2 |
Mode:
The modal class is 30-35 because it has the highest frequency, 10.
Here, l = 30, f1 = 10, f0 = 9, f2 = 3 and h = 5.
Mode = 30 + [(10 - 9)/(20 - 9 - 3)] × 5
= 30 + (1/8) × 5
= 30.625
Mode ≈ 30.63 students per teacher.
Mean:
Take a = 32.5 and h = 5.
| Students per teacher | fi | xi | ui | fiui |
| 15-20 | 3 | 17.5 | -3 | -9 |
| 20-25 | 8 | 22.5 | -2 | -16 |
| 25-30 | 9 | 27.5 | -1 | -9 |
| 30-35 | 10 | 32.5 | 0 | 0 |
| 35-40 | 3 | 37.5 | 1 | 3 |
| 40-45 | 0 | 42.5 | 2 | 0 |
| 45-50 | 0 | 47.5 | 3 | 0 |
| 50-55 | 2 | 52.5 | 4 | 8 |
| Total | 35 | -23 |
Mean = 32.5 + (-23/35) × 5
= 29.2143
Mean ≈ 29.21 students per teacher.
Answer: The mean ratio is approximately 29.21 students per teacher, while the modal ratio is approximately 30.63 students per teacher. Thus, the overall average is about 29 students per teacher, while the most common ratio is about 31 students per teacher.
Question 5: The following distribution shows the runs scored by some leading one-day international batsmen. Find the mode.
| Runs scored | Number of batsmen |
| 3000-4000 | 4 |
| 4000-5000 | 18 |
| 5000-6000 | 9 |
| 6000-7000 | 7 |
| 7000-8000 | 6 |
| 8000-9000 | 3 |
| 9000-10000 | 1 |
| 10000-11000 | 1 |
Solution:
The modal class is 4000-5000 because its frequency, 18, is the highest.
Here, l = 4000, f1 = 18, f0 = 4, f2 = 9 and h = 1000.
Mode = 4000 + [(18 - 4)/(36 - 4 - 9)] × 1000
= 4000 + (14/23) × 1000
= 4000 + 608.6957
= 4608.7 runs, approximately.
Answer: The mode is approximately 4608.7 runs.
Question 6: A student counted the number of cars passing a point on a road during 100 periods of three minutes each. Find the mode.
| Number of cars | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 7 | 14 | 13 | 12 | 20 | 11 | 15 | 8 |
Solution:
The highest frequency is 20, so the modal class is 40-50.
Here, l = 40, f1 = 20, f0 = 12, f2 = 11 and h = 10.
Mode = 40 + [(20 - 12)/(40 - 12 - 11)] × 10
= 40 + (8/17) × 10
= 44.7059
Answer: The mode is approximately 44.7 cars.
Question 1: The monthly electricity consumption of 68 consumers is given below. Find the mean, median and mode, and compare the three values.
| Monthly consumption in units | Number of consumers |
| 65-85 | 4 |
| 85-105 | 5 |
| 105-125 | 13 |
| 125-145 | 20 |
| 145-165 | 14 |
| 165-185 | 8 |
| 185-205 | 4 |
Mean:
Take a = 135 and h = 20.
| Consumption | fi | xi | ui | fiui |
| 65-85 | 4 | 75 | -3 | -12 |
| 85-105 | 5 | 95 | -2 | -10 |
| 105-125 | 13 | 115 | -1 | -13 |
| 125-145 | 20 | 135 | 0 | 0 |
| 145-165 | 14 | 155 | 1 | 14 |
| 165-185 | 8 | 175 | 2 | 16 |
| 185-205 | 4 | 195 | 3 | 12 |
| Total | 68 | 7 |
Mean = 135 + (7/68) × 20
= 137.0588
Mean ≈ 137.06 units.
Mode:
The modal class is 125-145.
Here, l = 125, f1 = 20, f0 = 13, f2 = 14 and h = 20.
Mode = 125 + [(20 - 13)/(40 - 13 - 14)] × 20
= 125 + (7/13) × 20
= 135.77 units, approximately.
Median:
Median = l + [((n/2) - cf)/f] × h
| Consumption | Frequency | Cumulative frequency |
| 65-85 | 4 | 4 |
| 85-105 | 5 | 9 |
| 105-125 | 13 | 22 |
| 125-145 | 20 | 42 |
| 145-165 | 14 | 56 |
| 165-185 | 8 | 64 |
| 185-205 | 4 | 68 |
n = 68, so n/2 = 34.
The first cumulative frequency greater than 34 is 42. Therefore, the median class is 125-145.
Here, l = 125, cf = 22, f = 20 and h = 20.
Median = 125 + [(34 - 22)/20] × 20
= 125 + 12
= 137 units
Answer: Mean = 137.06 units, median = 137 units and mode = 135.77 units. The three values are close to one another.
Question 2: The median of the following distribution is 28.5. Find x and y.
| Class interval | Frequency |
| 0-10 | 5 |
| 10-20 | x |
| 20-30 | 20 |
| 30-40 | 15 |
| 40-50 | y |
| 50-60 | 5 |
| Total | 60 |
Solution:
From the total frequency:
5 + x + 20 + 15 + y + 5 = 60
x + y + 45 = 60
x + y = 15 ...(1)
The given median, 28.5, lies in the class 20-30.
Therefore, l = 20, n = 60, cf = 5 + x, f = 20 and h = 10.
Median = l + [((n/2) - cf)/f] × h
28.5 = 20 + [(30 - 5 - x)/20] × 10
8.5 = (25 - x)/2
17 = 25 - x
x = 8
Using equation (1):
8 + y = 15
y = 7
Answer:x = 8 and y = 7.
Question 3: An insurance agent collected the following cumulative age data for 100 policyholders. Policies are issued only to people aged 18 years or more but below 60 years. Find the median age.
| Age | Number of policyholders |
| Below 20 | 2 |
| Below 25 | 6 |
| Below 30 | 24 |
| Below 35 | 45 |
| Below 40 | 78 |
| Below 45 | 89 |
| Below 50 | 92 |
| Below 55 | 98 |
| Below 60 | 100 |
Solution:
Convert the less-than cumulative frequencies into ordinary frequencies by subtracting each cumulative frequency from the next one.
| Age interval | Frequency | Cumulative frequency |
| 18-20 | 2 | 2 |
| 20-25 | 6 - 2 = 4 | 6 |
| 25-30 | 24 - 6 = 18 | 24 |
| 30-35 | 45 - 24 = 21 | 45 |
| 35-40 | 78 - 45 = 33 | 78 |
| 40-45 | 89 - 78 = 11 | 89 |
| 45-50 | 92 - 89 = 3 | 92 |
| 50-55 | 98 - 92 = 6 | 98 |
| 55-60 | 100 - 98 = 2 | 100 |
n = 100, so n/2 = 50.
The first cumulative frequency greater than 50 is 78. Hence, the median class is 35-40.
Here, l = 35, cf = 45, f = 33 and h = 5.
Median = 35 + [(50 - 45)/33] × 5
= 35 + 25/33
= 35.7576
Answer: The median age is approximately 35.76 years.
Question 4: The lengths of 40 leaves were measured to the nearest millimetre. Find the median length.
| Length in mm | Number of leaves |
| 118-126 | 3 |
| 127-135 | 5 |
| 136-144 | 9 |
| 145-153 | 12 |
| 154-162 | 5 |
| 163-171 | 4 |
| 172-180 | 2 |
Solution:
Because the measurements are correct to the nearest millimetre, convert the classes into continuous intervals by subtracting 0.5 from every lower limit and adding 0.5 to every upper limit.
| Continuous interval | Frequency | Cumulative frequency |
| 117.5-126.5 | 3 | 3 |
| 126.5-135.5 | 5 | 8 |
| 135.5-144.5 | 9 | 17 |
| 144.5-153.5 | 12 | 29 |
| 153.5-162.5 | 5 | 34 |
| 162.5-171.5 | 4 | 38 |
| 171.5-180.5 | 2 | 40 |
n = 40, so n/2 = 20.
The first cumulative frequency greater than 20 is 29. Thus, the median class is 144.5-153.5.
Here, l = 144.5, cf = 17, f = 12 and h = 9.
Median = 144.5 + [(20 - 17)/12] × 9
= 144.5 + 2.25
= 146.75 mm
Answer: The median length of the leaves is 146.75 mm.
| Lifetime in hours | Number of lamps |
| 1500-2000 | 14 |
| 2000-2500 | 56 |
| 2500-3000 | 60 |
| 3000-3500 | 86 |
| 3500-4000 | 74 |
| 4000-4500 | 62 |
| 4500-5000 | 48 |
Solution:
| Lifetime | Frequency | Cumulative frequency |
| 1500-2000 | 14 | 14 |
| 2000-2500 | 56 | 70 |
| 2500-3000 | 60 | 130 |
| 3000-3500 | 86 | 216 |
| 3500-4000 | 74 | 290 |
| 4000-4500 | 62 | 352 |
| 4500-5000 | 48 | 400 |
n = 400, so n/2 = 200.
The first cumulative frequency greater than 200 is 216. Therefore, the median class is 3000-3500.
Here, l = 3000, cf = 130, f = 86 and h = 500.
Median = 3000 + [(200 - 130)/86] × 500
= 3000 + (70/86) × 500
= 3406.9767 hours
Answer: The median lifetime is approximately 3406.98 hours.
Question 6: One hundred surnames were selected from a telephone directory. Their distribution according to the number of letters is given below. Find the median, mean and mode.
| Number of letters | Number of surnames |
| 1-4 | 6 |
| 4-7 | 30 |
| 7-10 | 40 |
| 10-13 | 16 |
| 13-16 | 4 |
| 16-19 | 4 |
Median:
| Number of letters | Frequency | Cumulative frequency |
| 1-4 | 6 | 6 |
| 4-7 | 30 | 36 |
| 7-10 | 40 | 76 |
| 10-13 | 16 | 92 |
| 13-16 | 4 | 96 |
| 16-19 | 4 | 100 |
n = 100, so n/2 = 50.
The median class is 7-10.
Here, l = 7, cf = 36, f = 40 and h = 3.
Median = 7 + [(50 - 36)/40] × 3
= 7 + 1.05
= 8.05 letters
Mean:
| Number of letters | fi | xi | fixi |
| 1-4 | 6 | 2.5 | 15 |
| 4-7 | 30 | 5.5 | 165 |
| 7-10 | 40 | 8.5 | 340 |
| 10-13 | 16 | 11.5 | 184 |
| 13-16 | 4 | 14.5 | 58 |
| 16-19 | 4 | 17.5 | 70 |
| Total | 100 | 832 |
Mean = 832/100
= 8.32 letters
Mode:
The modal class is 7-10.
Here, l = 7, f1 = 40, f0 = 30, f2 = 16 and h = 3.
Mode = 7 + [(40 - 30)/(80 - 30 - 16)] × 3
= 7 + (10/34) × 3
= 7.8824 letters
Answer: Median = 8.05 letters, mean = 8.32 letters and mode ≈ 7.88 letters.
Question 7: The following table gives the weights of 30 students. Find the median weight.
| Weight in kg | 40-45 | 45-50 | 50-55 | 55-60 | 60-65 | 65-70 | 70-75 |
| Number of students | 2 | 3 | 8 | 6 | 6 | 3 | 2 |
Solution:
| Weight in kg | Frequency | Cumulative frequency |
| 40-45 | 2 | 2 |
| 45-50 | 3 | 5 |
| 50-55 | 8 | 13 |
| 55-60 | 6 | 19 |
| 60-65 | 6 | 25 |
| 65-70 | 3 | 28 |
| 70-75 | 2 | 30 |
n = 30, so n/2 = 15.
The first cumulative frequency greater than 15 is 19. Therefore, the median class is 55-60.
Here, l = 55, cf = 13, f = 6 and h = 5.
Median = 55 + [(15 - 13)/6] × 5
= 55 + 10/6
= 56.6667 kg
Answer: The median weight is approximately 56.67 kg.
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NCERT Solutions for Class 10 Maths Chapter 13 Statistics 2026-27 provide clear and step-by-step answers to all the questions given in the NCERT textbook. They help students understand statistical concepts and solve numerical problems easily.
Chapter 13 Statistics mainly covers the mean, median, and mode of grouped data. Students learn different methods and formulas to calculate these values accurately.
These solutions help students understand difficult calculations, complete homework, revise important formulas, and prepare for examinations. The detailed steps also help students find and correct their mistakes.
Yes, the NCERT Solutions are very useful for Class 10 board exam preparation. They follow the NCERT syllabus and help students practise important questions that may be asked in school tests and board examinations.
Students can download the NCERT Solutions for Class 10 Maths Chapter 13 Statistics PDF from trusted educational platforms such as Infinity Learn. The PDF can be saved on a mobile phone, tablet, or computer for regular practice and quick revision.