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प्रश्न
Find the mean of each of the following frequency distributions
| Class interval | 50 - 70 | 70 - 90 | 90 - 110 | 110 - 130 | 130 - 150 | 150 - 170 |
| Frequency | 18 | 12 | 13 | 27 | 8 | 22 |
उत्तर
Let the a assumed mean be 100
| Class interval | Mid-value (x1) | d1 = x1 - 100 | `"u"_1 = (x_1 - 100)/20` | f1 | f1u1 |
| 50 - 70 | 60 | -40 | -2 | 18 | -36 |
| 70 - 90 | 80 | -20 | -1 | 12 | -12 |
| 90 - 110 | 100 | 0 | 0 | 13 | 0 |
| 110 - 130 | 120 | 20 | 1 | 27 | 27 |
| 130 - 150 | 140 | 40 | 2 | 8 | 16 |
| 150 - 170 | 160 | 60 | 3 | 22 | 66 |
| N = 100 | `sumf_1"u"_1=61` |
A = 100, h = 20
Mean `A+hxx(sumf_1"u"_1)/N`
`=100+20xx61/100`
`=100+1220/100`
= 100 + 12.20
= 112.20
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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 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 |
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|
Weekly wages
(Rupees)
|
0 - 2000 | 2000 - 4000 | 4000 - 6000 | 6000 - 8000 |
| No. of workers | 15 | 35 | 50 | 20 |
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| Tomatoes per Plant | 1 - 5 | 6 - 10 | 11 - 15 | 16 - 20 | 21 - 25 |
| Number of Plants | 20 | 50 | 46 | 22 | 12 |
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| Frequency | 4 | 6 | 10 | f | 6 | 4 |
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| Life time (in hours) | Number of lamps |
| 1500 – 2000 | 14 |
| 2000 – 2500 | 56 |
| 2500 – 3000 | 60 |
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| 3500 – 4000 | 74 |
| 4000 – 4500 | 62 |
| 4500 – 5000 | 48 |
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