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Published on: 13/05/2022
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Questions + Answers key
Take MCQ Maths Test1.
Find the mean, median and mode of the following distribution:
| Weight(in kgs) | 25-34 | 35-44 | 45-54 | 55-64 | 65-74 | 75-84 |
|---|---|---|---|---|---|---|
| Number of students | 4 | 8 | 10 | 14 | 8 | 6 |
2.
Find the mode of the following data:
| Marks | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
|---|---|---|---|---|---|
| Number of students | 22 | 38 | 46 | 34 | 20 |
3.
For the data 11, 15, 17, x+1, 19, x–2, 3 if the mean is 14 , find the value of x. Also find the mode of the data.
4.
The monthly salary of 10 employees in a factory are given below :
Rs. 5000, Rs. 7000, Rs. 5000, Rs. 7000, Rs. 8000, Rs. 7000, Rs. 7000, Rs. 8000, Rs. 7000, Rs. 5000. Find the mean, median and mode
5.
A researcher studying the behavior of mice has recorded the time (in seconds) taken by each mouse to locate its food by considering 13 different mice as 31, 33, 63, 33, 28, 29, 33, 27, 27, 34, 35, 28, 32. Find the median time that mice spent in searching its food.
6.
Find the Median of the given data: 36, 44, 86, 31, 37, 44, 86, 35, 60, 51
1.
| Weight in kgs | Number of Students f | Mid x | fx | cf |
| 24.5-34.5 | 4 | 29.5 | 118 | 4 |
| 34.5-44.5 | 8 | 39.5 | 316 | 12 |
| 44.5-54.5 | 10 | 49.5 | 495 | 22 |
| 54.5-64.5 | 14 | 59.5 | 833 | 36 |
| 64.5-74.5 | 8 | 69.5 | 556 | 44 |
| 74.5-84.5 | 6 | 79.5 | 477 | 50 |
| 50 | 2975 |
Mean\(\bar{x}=\cfrac{\Sigma fx}{\Sigma f}=\cfrac{2795}{50}=55.9\)
Median = \(\left(\cfrac{N}{2}\right)^{th} \) term is called the median class
N = 50
\(\cfrac{N}{2}=\cfrac{50}{2}=25\)
\(\therefore\) Median class = 25th value = 54.5 - 64.5
l = 54.5, m = 22, f = 14, c = 10
Median = \( l+\cfrac { \left( \cfrac { N }{ 2 } -m \right) }{ f } \times c\)
= 54.5 + \(\cfrac{25-22}{14}\times10\)
= 54.5 + \(\cfrac{3}{14}\times10\)
= 54.5 + \(\cfrac{30}{14}\)
= 54.5 + 2.14
= 56.64
Model class is 54.5 - 64.5 since it has the maximum frequency.
l = 54.5, f = 14, f1 = 10, f2 = 8, c = 10
\(\therefore\) Mode =\(l+\left[\cfrac{f-{f}_{1}}{2f-{f}_{1}{f}_{2}}\right]\times c\)
= 54.5+\(\left[\cfrac{14-10}{2\times 14-10-8}\right]\times 8\)
= 54.5+ \(\left(\cfrac{4}{28-18}\right)\times 10\)
= 54.5+ \(\cfrac{4}{10}\times 10=58.5\)
\(\therefore \) Mean = 55.9
Median = 56.64
Mode = 58.5
2.
| Marks | Number of Students |
| 0-10 | 22 |
| 10-20 | 38 |
| 20-30 | 46 |
| 30-40 | 34 |
| 40-50 | 20 |
Mode =\( l+\left[ \cfrac { f-{ f }_{ 1 } }{ 2f-{ f }_{ 1 }-{ f }_{ 2 } } \right] \times c\)
Here Model class 20-30 since ,it has the maximum frequency
l=20, f=46, f1=38. f2= 34, c = 30-20 =10
\(\therefore\) Mode = \( l+\left[ \cfrac { f-{ f }_{ 1 } }{ 2f-{ f }_{ 1 }-{ f }_{ 2 } } \right] \times c\)
= \(20+\left[\cfrac{46-38}{2\times46-38-34}\right]\times40\)

= 24
3.
Total of the data = 11 + 15 + 17 + x + 1 + 19 + x -2 + 3
= 2x + 64
Mean of the data = \(\frac{2 x+64}{7}\)
= 14 (given)
\(\frac{2 x+64}{7}=\frac{14}{1}\)
2x + 64 = 98
2x = 98 - 64
2x = 34
\(\therefore x=\frac{34}{2}=17\)
The data = 11, 15, 17, 17+1, 19, 17- 2, 3
= 3, 11, 15, 15, 17, 18, 19
15 occurs two times
\(\therefore\) The Mode of data = 15
4.
The monthly salary of 10 employees are Rs. 5000, Rs. 7000, Rs. 5000, Rs. 7000, Rs. 8000, Rs. 7000, Rs. 7000, Rs. 8000, Rs.7000, Rs. 5000
Writing in ascending order Rs. 5000, Rs. 5000, Rs. 5000, Rs. 7000, Rs. 7000, Rs. 7000, Rs. 8000, Rs. 8000
Number of values = 10 which is an even number.
Median = Average of \(\cfrac{{10}^{th}}{2} \) and \(\left(\cfrac{10}{2}+1\right)^{th}\)
\( \text {Mean } =\frac{(5000 \times 3)+(7000 \times 5)+(8000 \times 2)}{10} \)
\( =\frac{15000+35000+16000}{10} =\frac{66000}{10} \)
= Rs. 6600
\( \text { Median } =\text { Average of }\left(\frac{10}{2}\right)^{\text {th }} \text { and }\left(\frac{10}{2}+1\right)^{t h} \text { term } \)
\( =\text { Average of } 5^{\text {th }} \text { and } 6^{\text {th }} \text { term } \)
\(=\frac{7000+7000}{10}=\frac{14000}{2} = 7000\)
Median = Rs. 7000
Mode of salary = Rs. 7000
5.
Data in ascending order 27, 27, 28, 28, 29, 31, 32, 33, 33, 33, 34, 35, 63
Number of terms = 13
If n is odd rhen Median = \(\left[\frac{\mathrm{N}+1}{2}\right]^{t h}\) observation
\(=\left(\frac{13+1}{2}\right)^{t h}\)observation
= 7th observation
7th observation = 32
6.
Values in ascending order
31, 35, 36, 37, 44, 44, 51, 60, 86, 86
Number of terms = 10 which is even
Median = Average of \(\left[\frac{N}{2}\right]^{\text {th }} \text { term }+\left(\frac{n}{2}+1\right)^{\text {th }} \text { term }\)
= Average of [5th term + 6th term]
\(=\frac{44+44}{2}=44\)
Median = 44
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Tamilnadu Stateboard 9th Standard Subjects
Tamilnadu Stateboard Standards