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प्रश्न
Find the mean of the natural numbers from 3 to 12.
उत्तर
Numbers between 3 to 12 are 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12.
Here n = 10
`barx = (x_1 + x_2 + .... + x_n)/n`
∴ `barx = (3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12)/10`
= `75/10`
= 7.5
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संबंधित प्रश्न
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 age of 50 student of a class. Find the arithmetic mean of their ages.
| Age-years | 16 – 18 | 18 – 20 | 20 – 22 | 22 – 24 | 24 – 26 |
| No. of students | 2 | 7 | 21 | 17 | 3 |
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
A boy scored following marks in various class tests during a term; each test being marked out of 20.
15, 17, 16, 7, 10, 12, 14, 16, 19, 12 and 16
What are his mean marks?
Find the mean of all natural numbers from 32 to 46. Find the new mean when each number is diminished by 5.
Find the mode of the following frequency distribution:
| Hrs. Spent daily in studies | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 |
| No. of students | 8 | 7 | 3 | 5 | 10 | 6 | 3 | 4 |
Find the median of the given data: 36, 44, 86, 31, 37, 44, 86, 35, 60, 51
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.
The mean of five positive integers is twice their median. If four of the integers are 3, 4, 6, 9 and median is 6, then find the fifth integer
The median class for the given distribution is:
| Class Interval | 1 - 5 | 6 - 10 | 11 - 15 | 16 - 20 |
| Cumulative Frequency | 2 | 6 | 11 | 18 |
