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प्रश्न
The heights (in cm) of 8 girls of a class are 140, 142, 135, 133, 137, 150, 148 and 138 respectively. Find the mean height of these girls and their median height.
उत्तर
Arranging in ascending order: 133, 135, 137, 138, 140, 142, 148, 150
Here, the number of girls = 8 which is even
∴ Median =`1/2{"n"/2"th term"+("n"/2+1)"th term"}`
= `1/2{8/2"th term"+(8/2+1)"th term"}`
= `12` {4th term + 5th term}
= `1/2` {138 + 140} cm
= `1/2xx278`
= 139 cm
∴ Mean =`(133+135+137+138+140+142+148+150)/8`
= `1123/8`cm
= 140.375 cm
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संबंधित प्रश्न
The marks of 200 students in a test were recorded as follows:
| Marks | No. of students |
| 10-19 | 7 |
| 20-29 | 11 |
| 30-39 | 20 |
| 40-49 | 46 |
| 50-59 | 57 |
| 60-69 | 37 |
| 70-79 | 15 |
| 80-89 | 7 |
Construct the cumulative frequency table. Drew the ogive and use it too find:
(1) the median and
(2) the number of student who score more than 35% marks.
The marks obtained by 120 students in a mathematics test is given below:
| Marks | No. of students |
| 0 – 10 | 5 |
| 10 – 20 | 9 |
| 20 – 30 | 16 |
| 30 – 40 | 22 |
| 40 – 50 | 26 |
| 50 – 60 | 18 |
| 60 – 70 | 11 |
| 70 – 80 | 6 |
| 80 – 90 | 4 |
| 90 – 100 | 3 |
Draw an ogive for the given distributions on a graph sheet. Use a suitable scale for your ogive. Use your ogive to estimate:
- the median
- the number of student who obtained more than 75% in test.
- the number of students who did not pass in the test if the pass percentage was 40.
- the lower quartile.
Find the mean (correct to one place of decimal) by using short-cut method.
|
x |
40 |
41 |
43 |
45 |
46 |
49 |
50 |
|
f |
14 |
28 |
38 |
50 |
40 |
20 |
10 |
Find the mean of the following frequency distribution by the short cut method :
| Class | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
| Frequency | 9 | 12 | 15 | 10 | 14 |
Out of 10 students, who appeared in a test, three secured less than 30 marks and 3 secured more than 75 marks. The marks secured by the remaining 4 students are 35, 48, 66 and 40. Find the median score of the whole group.
The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, increased by 60%.
The mean of a certain number of observations is 32. Find the resulting mean, if the observation is decreased by 20%.
Find the median of 26, 33, 41, 18, 30, 22, 36, 45 and 24
Find the median of the following sets of numbers.
25, 11, 15, 10, 17, 6, 5, 12.
The following data has been arranged in ascending order.
0, 1, 2, 3, x + 1, x + 5, 20, 21, 26, 29.
Find the value of x, if the median is 5.
