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प्रश्न
What is the algebraic sum of deviation of a frequency distribution about its mean?
उत्तर
The algebraic sum of deviation of a frequency distribution about its mean is zero.
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संबंधित प्रश्न
Find the value of p, if the mean of the following distribution is 20.
| x | 15 | 17 | 19 | 20+P | 23 |
| f | 2 | 3 | 4 | 5P | 6 |
Candidates of four schools appear in a mathematics test. The data were as follows:-
| Schools | No. of Candidates | Average Score |
| I | 60 | 75 |
| II | 48 | 80 |
| III | NA | 55 |
| IV | 40 | 50 |
If the average score of the candidates of all the four schools is 66, find the number of candidates that appeared from school III.
If the mean of the following data is 18.75. Find the value of p.
| x | 10 | 15 | P | 25 | 30 |
| f | 5 | 10 | 7 | 8 | 2 |
If the mean of 25 observations is 27 and each observation is decreased by 7, what will be new mean?
The following table gives the literacy rate (in percentage) in 40 cities. Find the mean literacy rate, choosing a suitable method .
| Literacy rate(%) |
45 – 55 | 55 – 65 | 65 – 75 | 75 – 85 | 85 – 95 |
| Number of cities |
4 | 11 | 12 | 9 | 4 |
The mean of first n odd natural number is
Find the mean of the following distribution:
| Class interval | 0 - 10 | 10 - 20 | 20 - 30 | 30 - 40 | 40 - 50 |
| Frequency | 10 | 6 | 8 | 12 | 5 |
The marks obtained by a set of students in an examination all given below:
| Marks | 5 | 10 | 15 | 20 | 25 | 30 |
| Number of students | 6 | 4 | 6 | 12 | x | 4 |
Given that the mean marks of the set of students is 18, Calculate the numerical value of x.
If the mean of n observation ax1, ax2, ax3,....,axn is a`bar"X"`, show that `(ax_1 - abar"X") + (ax_2 - abar"X") + ...(ax_"n" - abar"X")` = 0.
Consider the following distribution of SO2 concentration in the air (in ppm = parts per million) in 30 localities. Find the mean SO2 concentration using assumed mean method. Also find the values of A, B and C.
| Class interval | Frequency (fi) | Class mark (xi) | di = xi - a |
| 0.00 - 0.04 | 4 | 0.02 | -0.08 |
| 0.04 - 0.08 | 9 | 0.06 | A |
| 0.08 - 0.12 | 9 | 0.10 | B |
| 0.12 - 0.16 | 2 | 0.14 | 0.04 |
| 0.16 - 0.20 | 4 | 0.18 | C |
| 0.20 - 0.24 | 2 | 0.22 | 0.12 |
| Total | `sumf_i=30` |
