Advertisements
Advertisements
प्रश्न
The following table gives the distribution of total household expenditure (in rupees) of manual workers in a city. Find the average expenditure (in rupees) per household.
| Expenditure (in rupees) (x1) |
Frequency(f1) |
| 100 - 150 | 24 |
| 150 - 200 | 40 |
| 200 - 250 | 33 |
| 250 - 300 | 28 |
| 300 - 350 | 30 |
| 350 - 400 | 22 |
| 400 - 450 | 16 |
| 450 - 500 | 7 |
उत्तर
Let the assumed mean (A) = 275
| Class interval |
Mid value (x1) | d1 = x1 - 275 | `"u"_1=(x_1-275)/50` | Frequency(f1) | f1u1 |
| 100 - 150 | 125 | -150 | -3 | 24 | -72 |
| 150 - 200 | 175 | -100 | -2 | 40 | -80 |
| 200 - 250 | 225 | -50 | -1 | 33 | -33 |
| 250 - 300 | 275 | 0 | 0 | 28 | 0 |
| 300 - 350 | 325 | 50 | 1 |
30 |
30 |
| 350 - 400 | 375 | 100 | 2 | 22 | 44 |
| 400 - 450 | 425 | 150 | 3 | 16 | 48 |
| 450 - 500 | 475 | 200 | 4 | 7 | 28 |
| N = 200 | `sumf_1"u"_1=-35` |
We have
A = 275, h = 50
Mean `=A+hxx(sumf_1"u"_1)/N`
`=275+50xx(-35)/200`
= 275 - 8.75
= 266.25
APPEARS IN
संबंधित प्रश्न
Find the value of p for the following distribution whose mean is 16.6
| x | 8 | 12 | 15 | P | 20 | 25 | 30 |
| f | 12 | 16 | 20 | 24 | 16 | 8 | 4 |
Find the missing frequency (p) for the following distribution whose mean is 7.68.
| x | 3 | 5 | 7 | 9 | 11 | 13 |
| f | 6 | 8 | 15 | P | 8 | 4 |
The following table gives the number of children of 150 families in a village. Find the average number of children per family.
| No. of children (x) | 0 | 1 | 2 | 3 | 4 | 5 |
| No. of families (f) | 10 | 21 | 55 | 42 | 15 | 7 |
In the first proof reading of a book containing 300 pages the following distribution of misprints was obtained:
| No. of misprints per page (x) | 0 | 1 | 2 | 3 | 4 | 5 |
| No. of pages (f) | 154 | 95 | 36 | 9 | 5 | 1 |
Find the average number of misprints per page.
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?
The mean of n observation is `overlineX` .f the first item is increased by 1, second by 2 and so on, then the new mean is
If the mean of observation \[x_1 , x_2 , . . . . , x_n is x\] then the mean of x1 + a, x2 + a, ....., xn + a is
The contents of 100 match box were checked to determine the number of match sticks they contained.
| Number of match sticks | Number of boxes |
| 35 | 6 |
| 36 | 10 |
| 37 | 18 |
| 38 | 25 |
| 39 | 21 |
| 40 | 12 |
| 41 | 8 |
(i) Calculate correct to one decimal place, the mean number of match sticks per box.
(ii) Determine how many matchsticks would have to be added. To the total contents of the 100 boxes to bring the mean up exactly 39 match sticks.
The average score of girls in class X examination in school is 67 and that of boys is 63. The average score for the whole class is 64.5. Find the percentage of girls and boys in the class.
The daily income of a sample of 50 employees are tabulated as follows:
| Income (in Rs) |
1 – 200 | 201 – 400 | 401 – 600 | 601 – 800 |
| Number of employees |
14 | 15 | 14 | 7 |
Find the mean daily income of employees.
