Finding the mean, median and mode is one of the first things you learn when studying statistics. The centre point of a data set can be described by these three metrics, which are referred to as measures of central tendency: mean, median, and mode.
Solving mean, median, and mode problems, real-world data analysis, and even business reporting requires an understanding of the mean median mode formula. This page covers mean, median and mode questions for Class 9 and 10 students following the CBSE/NCERT curriculum containing detailed definitions, formulas, and many mean median and mode questions with solutions to help you practice and learn effectively.
In statistics, the three most frequently used measures of central tendency are mean, median, and mode. They help describe the central value of a data set. Here's what each one means:
Mean (Average)
Definition: The mean is the sum of all values divided by the number of values.
Formula:
Mean = Sum of observations / Number of Observations
Example: Data: 4, 6, 8, 10
Mean = (4 + 6 + 8 + 10) ÷ 4 = 28 ÷ 4 = 7
Read more about arithmetic mean
Median
Definition: The median is the middle value when the numbers are arranged in ascending or descending order.
If the number of values is odd - middle value
If even - average of the two middle values
Example (Odd Number of Values):
Data: 3, 1, 5 - Ordered: 1, 3, 5 - Median = 3
Example (Even Number of Values):
Data: 2, 4, 6, 8 - Ordered: 2, 4, 6, 8 - Median = (4 + 6)/2 = 5
Read more about median
Mode
Definition: The mode is the number that appears most frequently in the data set.
One mode - Unimodal
Two modes - Bimodal
More than two - Multimodal
No repetition - No mode
One Mode (Unimodal):
Data: 3, 4, 4, 5, 6, 4 - Mode = 4 (appears 3 times)
Two Modes (Bimodal):
Data: 2, 3, 3, 5, 7, 7, 9 - Mode = 3 and 7 (both appear twice)
More than Two Modes (Multimodal):
Data: 1, 1, 2, 3, 3, 4, 5, 5, 6 - Mode = 1, 3 and 5 (all appear twice)
No Mode:
Data: 10, 20, 30, 40, 50 - Mode = No mode (no value repeats)
Read more about mode
Know more about related topics:
| Measure | Data Type | Formula | Variables / Description |
|---|---|---|---|
| Mean | Ungrouped Data | Mean = (Σx) / n | Σx = Sum of observations, n = Number of observations |
| Mean | Grouped Data (Direct Method) | Mean = (Σfᵢxᵢ) / Σfᵢ | fᵢ = Frequency, xᵢ = Midpoint (class mark) |
| Mean | Grouped Data (Assumed Mean Method) | Mean = a + (Σfᵢdᵢ / Σfᵢ) | a = Assumed mean, dᵢ = xᵢ - a |
| Mean | Grouped Data (Step-Deviation Method) | Mean = a + (Σfᵢuᵢ / Σfᵢ) × h | uᵢ = (xᵢ - a)/h, h = class width |
| Median | Ungrouped Data (Odd n) | Median = (n + 1)/2th observation | n = Number of observations |
| Median | Ungrouped Data (Even n) | Median = [(n/2)th observation + (n/2 + 1)th observation] / 2 | |
| Median | Grouped Data | Median = l + [(N/2 - cf)/f] × h | l = Lower boundary of median class, N = Total frequency, cf = Cumulative frequency before median class, f = Frequency of median class, h = Class width |
| Mode | Ungrouped Data | Mode = Most frequent value | |
| Mode | Grouped Data | Mode = l + [(f₁ - f₀) / (2f₁ - f₀ - f₂)] × h | l = Lower limit of modal class, f₁ = Frequency of modal class, f₀ = Frequency of class before, f₂ = Frequency of class after, h = Class width |
| Empirical Relation | - | Mode = 3 × Median - 2 × Mean | Used for moderately skewed distributions |
| Alternative Empirical Relation | - | Mean - Mode = 3 (Mean - Median) | Rearranged version of above |
Learn more about mean, median and mode
Data: 12, 15, 10, 18, 20
Step 1: Arrange the data in ascending order
Ordered = [10, 12, 15, 18, 20]
Step 2: Find the Mean
Mean = (10 + 12 + 15 + 18 + 20) ÷ 5 = 75 ÷ 5 = 15
Step 3: Find the Median
Number of values = 5 (odd) - Middle value = 3rd value
Median = 15
Step 4: Find the Mode
No value repeats - Mode = No mode
Data: 8, 10, 14, 18
Step 1: Arrange the data in ascending order
Ordered = [8, 10, 14, 18]
Step 2: Find the Mean
Mean = (8 + 10 + 14 + 18) ÷ 4 = 50 ÷ 4 = 12.5
Step 3: Find the Median
Number of values = 4 (even) - Average of 2nd and 3rd values
Median = (10 + 14) ÷ 2 = 12
Step 4: Find the Mode
No value repeats - Mode = No mode
Data: 4, 8, 6, 5, 3
Step 1: Arrange the data in ascending order
Ordered = [3, 4, 5, 6, 8]
Step 2: Find the Mean
Mean = (3 + 4 + 5 + 6 + 8) ÷ 5 = 26 ÷ 5 = 5.2
Step 3: Find the Median
Number of values = 5 (odd) - Middle value = 3rd value
Median = 5
Step 4: Find the Mode
No value repeats - Mode = No mode
Data: 14, 16, 20, 18, 16, 22, 24
Step 1: Arrange the data in ascending order
Ordered = [14, 16, 16, 18, 20, 22, 24]
Step 2: Find the Mean
Mean = (14 + 16 + 20 + 18 + 16 + 22 + 24) ÷ 7 = 130 ÷ 7 = 18.57
Step 3: Find the Median
Number of values = 7 (odd) - Middle value = 4th value
Median = 18
Step 4: Find the Mode
16 appears twice - Mode = 16
Data: 30, 40, 50, 60, 70, 80, 90, 100
Step 1: Arrange the data in ascending order
Ordered = [30, 40, 50, 60, 70, 80, 90, 100]
Step 2: Find the Mean
Mean = (30 + 40 + 50 + 60 + 70 + 80 + 90 + 100) ÷ 8 = 520 ÷ 8 = 65
Step 3: Find the Median
Number of values = 8 (even) - Average of 4th and 5th values
Median = (60 + 70) ÷ 2 = 65
Step 4: Find the Mode
No value repeats - Mode = No mode
Data: 11, 12, 13, 12, 14, 15, 12, 16
Step 1: Arrange the data in ascending order
Ordered = [11, 12, 12, 12, 13, 14, 15, 16]
Step 2: Find the Mean
Mean = (11 + 12 + 13 + 12 + 14 + 15 + 12 + 16) ÷ 8 = 105 ÷ 8 = 13.13
Step 3: Find the Median
Number of values = 8 (even) - Average of 4th and 5th values
Median = (12 + 13) ÷ 2 = 12.5
Step 4: Find the Mode
12 appears 3 times - Mode = 12
Data: 3, 5, 5, 5, 7, 9, 11, 13
Step 1: Arrange the data in ascending order
Ordered = [3, 5, 5, 5, 7, 9, 11, 13]
Step 2: Find the Mean
Mean = (3 + 5 + 5 + 5 + 7 + 9 + 11 + 13) ÷ 8 = 58 ÷ 8 = 7.25
Step 3: Find the Median
Number of values = 8 (even) - Average of 4th and 5th values
Median = (5 + 7) ÷ 2 = 6
Step 4: Find the Mode
5 appears 3 times - Mode = 5
Read more:
Solution:
Sum = 15 + 20 + 25 + 30 + 35 = 125
Number of values = 5
Mean = 125 ÷ 5 = 25
Solution:
4 appears 4 times - most frequent value.
Mode = 4
Solution:
Arranged in order: 3, 7, 9, 11, 15
Number of values = 5 (odd)
Middle value = 3rd value
Median = 9
Solution:
Mean = Sum ÷ Number of values
18 = Sum ÷ 5
Sum = 18 × 5 = 90
Solution:
Arranged: 6, 6, 6, 8, 8, 10, 12
Mean = (6+8+6+10+12+8+6) ÷ 7 = 56 ÷ 7 = 8
Median = 4th value = 8
Mode = 6 (appears 3 times)
Answer: Mean = 8, Median = 8, Mode = 6
Solution:
Total sum = 12 × 6 = 72
Sum of 5 known values = 10 + 14 + 8 + 16 + 11 = 59
Sixth observation = 72 - 59 = 13
Solution:
Arranged: 12, 21, 23, 34, 45, 56, 67, 89
Number of values = 8 (even)
Median = (4th + 5th) ÷ 2 = (34 + 45) ÷ 2 = 79 ÷ 2 = 39.5
Solution:
7 already appears 3 times and is the mode regardless of x.
x should not create another mode - x can be any value other than 5, 3, or 9.
x = 2 (or any value that does not appear more than 3 times)
Solution:
Data: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Mean = 55 ÷ 10 = 5.5
Median = (5th + 6th) ÷ 2 = (5+6) ÷ 2 = 5.5
Mode = No mode (all values appear once)
Answer: Mean = 5.5, Median = 5.5, Mode = No mode
Solution:
Mode = 3 × Median - 2 × Mean
65 = 3 × Median - 2 × 61.5
65 = 3 × Median - 123
3 × Median = 188
Median = 188 ÷ 3 = 62.67
| Class | Frequency |
|---|---|
| 0-10 | 3 |
| 10-20 | 7 |
| 20-30 | 12 |
| 30-40 | 10 |
| 40-50 | 8 |
Mean (Direct Method):
| Class | fi | xi | fi × xi |
|---|---|---|---|
| 0-10 | 3 | 5 | 15 |
| 10-20 | 7 | 15 | 105 |
| 20-30 | 12 | 25 | 300 |
| 30-40 | 10 | 35 | 350 |
| 40-50 | 8 | 45 | 360 |
∑fi = 40, ∑fi × xi = 1130
Mean = 1130 ÷ 40 = 28.25
Median:
n = 40, n/2 = 20 - Median class = 20-30
l = 20, f = 12, cf = 10, h = 10
Median = 20 + [(20-10)/12] × 10 = 20 + 8.33 = 28.33
Mode:
Highest frequency = 12 - Modal class = 20-30
l = 20, f1 = 12, f0 = 7, f2 = 10, h = 10
Mode = 20 + [(12-7)/(24-7-10)] × 10 = 20 + (5/7) × 10 = 27.14
Empirical Verification:
3 × Median - 2 × Mean = 3 × 28.33 - 2 × 28.25 = 84.99 - 56.5 = 28.49 ≈ Mode [which is correct]
| Class | fi | xi | ui = (xi-30)/10 | fi × ui |
|---|---|---|---|---|
| 10-20 | 4 | 15 | -2 | -8 |
| 20-30 | 8 | 25 | -1 | -8 |
| 30-40 | 14 | 35 | 0 | 0 |
| 40-50 | 10 | 45 | 1 | 10 |
| 50-60 | 4 | 55 | 2 | 8 |
∑fi = 40, ∑fi × ui = 2
Mean = 30 + (2/40) × 10 = 30 + 0.5 = 30.5
| Class Interval | Frequency |
|---|---|
| 0 - 10 | 5 |
| 10 - 20 | 8 |
| 20 - 30 | 20 |
| 30 - 40 | 10 |
| 40 - 50 | 7 |
n = 50, n/2 = 25 - Median class = 20-30
l = 20, f = 20, cf = 13, h = 10
Median = 20 + [(25-13)/20] × 10 = 20 + 6 = 26
| Class Interval | Frequency |
|---|---|
| 5 - 15 | 6 |
| 15 - 25 | 11 |
| 25 - 35 | 21 |
| 35 - 45 | 9 |
| 45 - 55 | 3 |
Highest frequency = 21 - Modal class = 25-35
l = 25, f1 = 21, f0 = 11, f2 = 9, h = 10
Mode = 25 + [(21-11)/(42-11-9)] × 10 = 25 + (10/22) × 10 = 25 + 4.55 = 29.55
Mode = 3 × Median - 2 × Mean
Mode = 3 × 50.4 - 2 × 53
Mode = 151.2 - 106 = 45.2
Mean = (56 + 67 + 56 + 78 + 90)/5 = 347/5 = 69.4
Ordered = [56, 56, 67, 78, 90]
Median = 67
Mode = 56
Mean = 22/7 = 3.14
Ordered = [2, 2, 3, 3, 3, 4, 5]
Median = 4th value = 3
Mode = 3
| Books Read | Number of Students |
|---|---|
| 0 - 5 | 4 |
| 6 - 10 | 6 |
| 11 - 15 | 10 |
| 16 - 20 | 6 |
| 21 - 25 | 4 |
Find the mean number of books read using the direct method.
Solution: Classmarks (xi): 2.5, 8, 13, 18, 23
fi: 4, 6, 10, 6, 4
fi × xi: 10, 48, 130, 108, 92
∑fi = 30, ∑fi × xi = 388
Mean = 388 ÷ 30 = 12.93
| Age Group | Frequency |
|---|---|
| 0-10 | 2 |
| 10-20 | 4 |
| 20-30 | 8 |
| 30-40 | 12 |
| 40-50 | 9 |
| 50-60 | 5 |
Find the median age.
Solution: Total frequency = 40
n/2 = 20 - Median class = 30-40
l = 30, f = 12, F = 14, h = 10
Median = 30 + [(20 - 14) / 12] × 10 = 30 + 5 = 35
A survey was conducted to know how many hours students study per day:
| Hours Studied | Number of Students |
|---|---|
| 0 - 2 | 5 |
| 2 - 4 | 9 |
| 4 - 6 | 15 |
| 6 - 8 | 10 |
| 8 - 10 | 6 |
Find the mode of study hours.
Solution:
Modal class = 4-6
l = 4, f1 = 15, f0 = 9, f2 = 10, h = 2
Mode = 4 + [(15 - 9) / (2×15 - 9 - 10)] × 2
= 4 + (6 / 11) × 2 = 4 + 1.09 = 5.09 hours
1. Find the mean of: 5, 10, 15, 20, 25, 30
2. Find the mode of: 3, 5, 7, 5, 9, 5, 3, 7, 5
3. Find the median of: 42, 38, 55, 29, 61
4. The mean of 8 numbers is 35. Seven of them are 28, 31, 40, 36, 29, 38, 42. Find the eighth number.
5. Find the median of: 102, 98, 87, 115, 76, 134, 91, 110
6. If mean = 40 and median = 42, find the mode using the empirical formula.
7. The ages of 7 students are: 14, 16, 15, 14, 17, 14, 16. Find the mean, median, and mode.
8. Find the mean using the assumed mean method (a = 25):
| Class | Frequency |
|---|---|
| 0 - 10 | 2 |
| 10 - 20 | 6 |
| 20 - 30 | 10 |
| 30 - 40 | 8 |
| 40 - 50 | 4 |
9. Find the median:
| Class | Frequency |
|---|---|
| 10 - 20 | 4 |
| 20 - 30 | 9 |
| 30 - 40 | 15 |
| 40 - 50 | 12 |
| 50 - 60 | 6 |
10. Find the mode:
| Class | Frequency |
|---|---|
| 20 - 30 | 5 |
| 30 - 40 | 12 |
| 40 - 50 | 18 |
| 50 - 60 | 10 |
| 60 - 70 | 4 |
Answers to practice questions
Always order the data set before calculating the median or identifying mode.
Use the mean median mode formula carefully.
For large data sets, double-check values and totals.
Be aware of bimodal or multimodal data.
Solve multiple mean median mode questions with solutions for practice.
In statistics, the mean, median, and mode are fundamental tools for interpreting data. The mode is the number that appears most frequently, the mean is the average, and the median is the middle value. Finding the median, mean, and mode makes it easier to solve problems in the real world and on tests. You can improve your skills and confidently solve data problems by practicing various mean median mode questions with answers and applying the proper mean median mode formula.
Answer: Mean is the average of all values, calculated by dividing the sum by the count. Median is the middle value when data is arranged in order. Mode is the value that appears most frequently. Each measures central tendency differently - mean uses all values, median uses position, mode uses frequency.
Answer: Ordered Data: 12, 12, 13, 13, 14, 14, 14, 16, 19
Mean = (13 + 16 + 12 + 14 + 19 + 12 + 14 + 13 + 14) ÷ 9 = 127 ÷ 9 = 14.11
Median = 5th number = 14
Mode = 14 (appears 3 times)
Answer:
Mean = (Sum of all values) ÷ (Number of values)
Median = Middle value (or average of two middle values if even number of terms)
Mode = Most frequent value in the data set
Answer:
Arrange the numbers in order.
If count is odd - pick the middle number.
If count is even - take the average of the two middle numbers.
Answer:
For grouped data:
Mode = L + (f₁ - f₀) / (2f₁ - f₀ - f₂) × h
Where:
L = lower limit of modal class
f₁ = frequency of modal class
f₀ = frequency of class before
f₂ = frequency of class after
h = class width
Answer: Use mean when data has no extreme values and all values matter equally. Use median when data has outliers or is skewed - for example, income data. Use mode when you need the most common value - for example, the most popular shoe size or exam score.
Master maths concepts like mean, median, and mode with Orchids The International School.
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