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प्रश्न
The algebraic sum of the deviations of a set of n values from their mean is
पर्याय
0
n – 1
n
n + 1
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उत्तर
The algebraic sum of the deviations of a set of n values from their mean is 0
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संबंधित प्रश्न
The mean of 5 observations is 50. One of the observations was removed from the data, hence the mean became 45. Find the observation which was removed.
The following table shows the number of saplings planted by 30 students. Fill in the boxes and find the average number of saplings planted by each student.
| No. of saplings (Scores) xi |
No. of students (frequency) fi |
fi x xi |
| 1 | 4 | 4 |
| 2 | 6 | `square` |
| 3 | 12 | `square` |
| 4 | 8 | `square` |
| N = `square` | ∑fixi = `square` |
Mean `bar "x"` = `square/"N"`
= `square/square`
= `square`
∴ The average number of trees planted `square`
The following table shows the electricity (in units) used by 25 families of Eklara village in a month of May. Complete the table and answer the following questions.
| Electricity used (units) `bb(x_i)` |
No. of Families (frequency) `bb(f_i)` |
`bb(f_ix_i)` |
| 30 | 7 | _________ |
| 45 | 2 | __________ |
| 60 | 8 | __________ |
| 75 | 5 | __________ |
| 90 | 3 | __________ |
| N = _________ | `sum f_ix_i` = ______ |
- How many families use 45 units electricity?
- State the score, the frequency of which is 5.
- Find N, and `sum f_ix_i`
- Find the mean of electricity used by each family in the month of May.
In a class test in mathematics, 10 students scored 75 marks, 12 students scored 60 marks, 8 students scored 40 marks and 3 students scored 30 marks. Find the mean of their score
Arithmetic mean of 10 observations was found to be 22. If one more observation 44 was to be added to the data, what would be the new mean?
The average of two numbers are 20. One number is 24, another number is ____________
If the arithmetic mean of 8, 4, x, 6, 2, 7 is 5, then the value of x is ______.
Mean can never be a fraction.
The marks in a subject for 12 students are as follows:
31, 37, 35, 38, 42, 23, 17, 18, 35, 25, 35, 29
For the given data, find the mean
In a class of 100 students there are 70 boys whose average marks in a subject are 75. If the average marks of the complete class is 72, then what is the average of the girls?
