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प्रश्न
30 children were asked about the number of hours they watched TV programmes last week. The results are recorded as under:
| Number of hours | 0 – 5 | 5 – 10 | 10 – 15 | 15 – 20 |
| Frequency | 8 | 16 | 4 | 2 |
Can we say that the number of children who watched TV for 10 or more hours a week is 22? Justify your answer.
उत्तर
No, in fact the number of children who watched TV for 10 or more hour in a week is 4 + 2 i.e.,6.
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संबंधित प्रश्न
Write the class size and class limits in each of the following:
(i) 104, 114, 124, 134, 144, 154, and 164
(ii) 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97 and 102
(iii) 12.5, 17.5, 22.5, 27.5, 32.5, 37.5, 42.5, 47.5
The daily minimum temperatures in degrees Ce1siu& recorded in a certain Arctic region are
as follows:
−12.5, −10.8, −18.6, −8.4, −10.8, −4.2, −4.8, −6.7, −13.2, −11.8, −2.3, 1.2, 2.6, 0, 2.4,
0, 3.2, 2.7, 3.4, 0, − 2.4, − 2.4, 0, 3.2, 2.7, 3.4, 0, − 2.4, − 5.8, -8.9, 14.6, 12.3, 11.5, 7.8,2.9.
Represent them as frequency distribution table taking − 19.9 to − 15 as the first class
interval.
Thirty children were asked about the number of hours they watched T.V. programmers in the previous week. The results were found as follows:
| 1 | 6 | 2 | 3 | 5 | 12 | 5 | 8 | 4 | 8 |
| 10 | 3 | 4 | 12 | 2 | 8 | 15 | 1 | 17 | 6 |
| 3 | 2 | 8 | 5 | 9 | 6 | 8 | 7 | 14 | 12 |
(i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5 – 10.
(ii)How many children watched television for 15 or more hours a week?
The following cumulative frequency distribution table shows the daily electricity consumption (in kW) of 40 factories in an industrial state:
| Consumption (in kW) | No. of Factories |
| Below 240 | 1 |
| Below 270 | 4 |
| Below 300 | 8 |
| Below 330 | 24 |
| Below 360 | 33 |
| Below 390 | 38 |
| Below 420 | 40 |
(i) Represent this as a frequency distribution table.
(ii) Prepare a cumulative frequency table.
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In a frequency distribution, the mid-value of a class is 15 and the class intervals is 4. The lower limit of the class is
The number of times a particular item occurs in a given data is called its
Tallys are usually marked in a bunch of
For drawing a frequency polygon of a continous frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abcissae are respectively ______.
The following are the marks (out of 100) of 60 students in mathematics.
16, 13, 5, 80, 86, 7, 51, 48, 24, 56, 70, 19, 61, 17, 16, 36, 34, 42, 34, 35, 72, 55, 75, 31, 52, 28, 72, 97, 74, 45, 62, 68, 86, 35, 85, 36, 81, 75, 55, 26, 95, 31, 7, 78, 92, 62, 52, 56, 15, 63, 25, 36, 54, 44, 47, 27, 72, 17, 4, 30.
Construct a grouped frequency distribution table with width 10 of each class starting from 0 – 9.
