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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 mean of the following distribution is 52 and the frequency of class interval 30-40 is ‘f’. Find ‘f’.
| Class Interval | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 5 | 3 | f | 7 | 2 | 6 | 13 |
From the data given below, calculate the mean wage, correct to the nearest rupee.
| Category | A | B | C | D | E | F |
| Wages (Rs/day) | 50 | 60 | 70 | 80 | 90 | 100 |
| No. of workers | 2 | 4 | 8 | 12 | 10 | 6 |
- If the number of workers in each category is doubled, what would be the new mean wage?
- If the wages per day in each category are increased by 60%; what is the new mean wage?
- If the number of workers in each category is doubled and the wages per day per worker are reduced by 40%, what would be the new mean wage?
The following are the marks obtained by 70 boys in a class test:
| Marks | No. of boys |
| 30 – 40 | 10 |
| 40 – 50 | 12 |
| 50 – 60 | 14 |
| 60 – 70 | 12 |
| 70 – 80 | 9 |
| 80 – 90 | 7 |
| 90 – 100 | 6 |
Calculate the mean by:
Step-deviation method
By drawing an ogive, estimate the median for the following frequency distribution:
| Weight (kg) | 10 – 15 | 15 – 20 | 20 – 25 | 25 – 30 | 30 – 35 |
| No. of boys | 11 | 25 | 12 | 5 | 2 |
In a school, 100 pupils have heights as tabulate below:
| Height (in cm) | No. of pupils |
| 121 – 130 | 12 |
| 131 – 140 | 16 |
| 141 – 150 | 30 |
| 151 – 160 | 20 |
| 161 – 170 | 14 |
| 171 – 180 | 8 |
Find the median height by drawing an ogive.
The following table shows the expenditure of 60 boys on books. Find the mode of their expenditure:
| Expenditure (Rs) | No. of students |
| 20 – 25 | 4 |
| 25 – 30 | 7 |
| 30 – 35 | 23 |
| 35 – 40 | 18 |
| 40 – 45 | 6 |
| 45 – 50 | 2 |
Find the mean of first 12 even numbers.
Estimate the median, the lower quartile and the upper quartile of the following frequency distribution by drawing an ogive:
| Age( in yrs) | Under 10 | Under 20 | Under 30 | Under 40 | Under 50 | Under 60 |
| No. of males | 6 | 10 | 25 | 32 | 43 | 50 |
Estimate the median, the lower quartile and the upper quartile of the following frequency distribution by drawing an ogive:
| Marks (less than) | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 |
| No. of students | 5 | 15 | 30 | 54 | 72 | 86 | 94 | 100 |
If the mean of 6, 4, 7, p and 10 is 8, find the value of p.
