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प्रश्न
Calculate the mean of the following distribution :
| Class Interval | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Frequency | 8 | 5 | 12 | 35 | 24 | 16 |
उत्तर
Consider the following distribution:
| Class Interval | Frequency (f) | Classmark (x) | fx |
| 0 – 10 | 8 | 5 | 40 |
| 10 – 20 | 5 | 15 | 75 |
| 20 – 30 | 12 | 25 | 300 |
| 30 – 40 | 35 | 35 | 1225 |
| 40 – 50 | 24 | 45 | 1080 |
| 50 – 60 | 16 | 55 | 880 |
| Total | `n = sum f = 100` | `sum fx = 3600` |
Mean = `(sum fx)/n = 3600/100 = 36`
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संबंधित प्रश्न
Calculate the mean of the following distribution using step deviation method.
| Marks | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Number of students |
10 | 9 | 25 | 0 | 16 | 10 |
Marks obtained (in mathematics) by 9 student are given below:
60, 67, 52, 76, 50, 51, 74, 45 and 56
if marks of each student be increased by 4; what will be the new value of arithmetic mean.
Attempt this question on graph paper.
| Age (yrs ) | 5-15 | 15-25 | 25-35 | 35-45 | 45-55 | 55-65 | 65-75 |
| No.of casualties | 6 | 10 | 15 | 13 | 24 | 8 | 7 |
(1) Construct the 'less than' Cumulative frequency curve for the above data. using 2 cm =10 years on one axis and 2 cm =10 casualties on the other.
(2)From your graph determine :
(a)the median
(b)the lower quartile
Using a graph paper, draw an ogive for the following distribution which shows a record of the width in kilograms of 200 students.
| Weight | Frequency |
| 40 – 45 | 5 |
| 45 – 50 | 17 |
| 50 – 55 | 22 |
| 55 – 60 | 45 |
| 60 – 65 | 51 |
| 65 – 70 | 31 |
| 70 – 75 | 20 |
| 75 – 80 | 9 |
Use your ogive to estimate the following:
- The percentage of student weighting 55 kg or more
- The weight above which the heaviest 30% of the student fall
- The number of students who are
- underweight
- overweight, If 55.70 kg is considered as standard weight.
The weights of 11 students in a class are 36 kg, 45 kg, 44 kg, 37 kg, 36 kg, 41 kg, 45 kg, 43 kg, 39 kg, 42 kg and 40 kg. Find the median of their weights.
The marks obtained by 200 students in an examination are given below :
| Marks | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 | 80-90 | 90-100 |
| No.of students | 5 | 10 | 11 | 20 | 27 | 38 | 40 | 29 | 14 | 6 |
Using a graph paper, draw an Ogive for the above distribution. Use your Ogive to estimate:
(i) the median;
(ii) the lower quartile;
(iii) the number of students who obtained more than 80% marks in the examination and
(iv) the number of students who did not pass, if the pass percentage was 35.
Use the scale as 2 cm = 10 marks on one axis and 2 cm = 20 students on the other axis.
If different values of variable x are 19.8, 15.4, 13.7, 11.71, 11.8, 12.6, 12.8, 18.6, 20.5 and 2.1, find the mean.
Find the median of 17, 23, 36, 12, 18, 23, 40 and 20
Find the mean and the median of: 10,12, 12, 15, 15, 17, 18, 18, 18 and 19
Find the median of the given data:
14, −3, 0, −2, −8, 13, −1, 7
