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प्रश्न
If the mean of the following distribution is 2.6, then the value of y is:
| Variable (x) | 1 | 2 | 3 | 4 | 5 |
| Frequency | 4 | 5 | y | 1 | 2 |
विकल्प
3
8
13
24
उत्तर
8
Explanation:
Consider the following table:
| Variable (x) | Frequency (f) |
fx |
| 1 | 4 | 4 |
| 2 | 5 | 10 |
| 3 | y | 3y |
| 4 | 1 | 4 |
| 5 | 2 | 10 |
| ∑f = 12 + y | ∑fx = 28 + 3y |
Now,
Mean = `(sum"fx")/(sum"f")`
`2.6/1 = (28 + 3y)/(12+y)`
31.2 + 2.6y = 28 + 3y
3y – 2.6y = 31.2 – 28
0.4y = 3.2
y = `(3.2)/(0.4)`
y = 8
संबंधित प्रश्न
Consider the following distribution of daily wages of 50 worker of a factory.
|
Daily wages (in Rs) |
100 − 120 |
120 − 140 |
140 −1 60 |
160 − 180 |
180 − 200 |
|
Number of workers |
12 |
14 |
8 |
6 |
10 |
Find the mean daily wages of the workers of the factory by using an appropriate method.
Find the mean of each of the following frequency distributions
| Class interval | 0 - 8 | 8 - 16 | 16 - 24 | 24 - 32 | 32 - 40 |
| Frequency | 6 | 7 | 10 | 8 | 9 |
The following distribution shows the daily pocket allowance given to the children of a multistorey building. The average pocket allowance is Rs 18.00. Find out the missing frequency.
| Class interval | 11 - 13 | 13 - 15 | 15 - 17 | 17 - 19 | 19 - 21 | 21 - 23 | 23 - 25 |
| Frequency | 7 | 6 | 9 | 13 | - | 5 | 4 |
Using an appropriate method, find the mean of the following frequency distribution:
| Class | 84-90 | 90-96 | 96-102 | 102-108 | 108-114 | 114-120 |
| Frequency | 8 | 10 | 16 | 23 | 12 | 11 |
Which method did you use, and why?
In an annual examination, marks (out of 90) obtained by students of Class X in mathematics are given below:
| Marks Obtained |
0 – 15 | 15 – 30 | 30 – 45 | 45 – 60 | 60 – 75 | 75 – 90 |
| Number of students |
2 | 4 | 5 | 20 | 9 | 10 |
Find the mean marks.
Find the mean of the following data using step-deviation method:
| Class | 500 – 520 | 520 – 540 | 540 – 560 | 560 – 580 | 580 – 600 | 600 – 620 |
| Frequency | 14 | 9 | 5 | 4 | 3 | 5 |
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If the mean of frequency distribution is 8.1 and Σfixi = 132 + 5k, Σfi = 20, then k =?
While computing mean of grouped data, we assume that the frequencies are ______.
If the mean of 9, 8, 10, x, 14 is 11, find the value of x.
