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प्रश्न
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 |
उत्तर
| Weight (kg) | No. of boys | Cumulative Frequency |
| 10 – 15 | 11 | 11 |
| 15 – 20 | 25 | 36 |
| 20 – 25 | 12 | 48 |
| 25 – 30 | 5 | 53 |
| 30 – 35 | 2 | 55 |
Number of terms = 55
∴ Median = `(55 + 1^(th))/2` term
= 28th term
Through mark of 28 on the y-axis, draw a line parallel to x-axis which meets the curve at A. From A, draw a perpendicular to x-axis, which meets x-axis at B.
The value of B is the median which is 18.4 kg.
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संबंधित 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 |
Find the mean of the natural numbers from 3 to 12.
The ages of 40 students are given in the following table :
| Age (in years) | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| Frequency | 2 | 4 | 6 | 9 | 8 | 7 | 4 |
Find the arithmetic mean.
The following table gives the heights of plants in centimeter. If the mean height of plants is 60.95 cm; find the value of 'f'.
| Height (cm) | 50 | 55 | 58 | 60 | 65 | 70 | 71 |
| No. of plants | 2 | 4 | 10 | f | 5 | 4 | 3 |
The contents of 100 match boxes were checked to determine the number of matches they contained.
| No. of matches | 35 | 36 | 37 | 38 | 39 | 40 | 41 |
| No. of boxes | 6 | 10 | 18 | 25 | 21 | 12 | 8 |
- Calculate, correct to one decimal place, the mean number of matches per box.
- Determine, how many extra matches would have to be added to the total contents of the 100 boxes to bring the mean up to exactly 39 matches.
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:
Short-cut method
Find the arithmetic mean (correct to the nearest whole number) by using step-deviation method.
| x | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| f | 20 | 43 | 75 | 67 | 72 | 45 | 39 | 9 | 8 | 6 |
Find the median of all prime numbers between 20 and 50
Find the median of the following:
3x, x+5, x+7, x+9, x+11, x+13
Find the median of:
241, 243, 347, 350, 327, 299, 261, 292, 271, 258 and 257
