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प्रश्न
The time taken, in seconds, to solve a problem by each of 25 pupils is as follows:
16, 20, 26, 27, 28, 30, 33, 37, 38, 40, 42, 43, 46, 46, 46, 48, 49, 50, 53, 58, 59, 60, 64, 52, 20
(a) Construct a frequency distribution for these data, using a class interval of 10 seconds.
(b) Draw a histogram to represent the frequency distribution.
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उत्तर
Given that the times (in seconds) taken to solve a problem by each of 25 pupils are 16, 20, 26, 27, 28, 30, 33, 37, 38, 40, 42, 43, 46, 46, 46, 48, 49, 50, 53, 58, 59, 60, 64, 52 and 20. The minimum and maximum time values are 16 and 64 respectively.
(a) At first construct the following frequency distribution for the given data. Since, the lowest value is 16; we start with the class-interval 15-25, as the class size must be 10.
| Class - Intervals | Tally | Frequency |
| 15-25 | lll | 3 |
| 25-35 | lllll | 5 |
| 35-45 | lllll | 5 |
| 45-55 | llllllll | 8 |
| 55-65 | llll | 4 |
(b) To represent the given data by a histogram, we first draw horizontal and vertical axes. Let us consider that the horizontal and vertical axes represent the class-limits and the frequencies of the class-intervals respectively.
The above data is a continuous grouped frequency distribution with equal class-intervals, which is 10. Construct rectangles with class-intervals as bases and respective frequencies as heights.
The histogram of the data in part (a) is as follows:

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संबंधित प्रश्न
Read the bar graph given in Fig. 23.19 and answer the following questions:
(i) What information is given by the bar graph?

(ii) In which years the areas under the sugarcane crop were the maximum and the minimum?
(iii) State whether true or false:
The area under the sugarcane crop in the year 1982 - 83 is three times that of the year 1950 - 51
Read the bar graph given in Fig. 23.20 and answer the fol1owing questions:

(i) What information is given by the bar graph?
(ii) What was the expenditure on health and family planning in the year 1982-83?
(iii) In which year is the increase in expenditure maximum over the expenditure in previous year? What is the maximum increase?
Read the following bar graph and answer the following questions:
(i) What information is given by the bar graph?
(ii) In which year the export is minimum?
(iii)In which year the import is maximum?
(iv)In which year the difference of the values of export and import is maximum?

The following data gives the production of foodgrains (in thousand tonnes) for some years:
| Year | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 |
| Production (in thousand tonnes |
120 | 150 | 140 | 180 | 170 | 190 |
Represent the above with the help of a bar graph.
The production of oil (in lakh tonnes) in some of the refineries in India during 1982 was given below:
| Refinery: | Barauni | Koyali | Mathura | Mumbai | Florida |
| Production of oil (in lakh tonnes) |
30 | 70 | 40 | 45 | 25 |
Construct a bar graph to represent the above data so that the bars are drawn horizontally.
Construct a histogram for the following data:
| Monthly School fee (in Rs): |
30-60 | 60-90 | 90-120 | 120-150 | 150-180 | 180-210 | 210-240 |
| No of Schools | 5 | 12 | 14 | 18 | 10 | 9 | 4 |
In a histogram, each class rectangle is constructed with base as
Draw frequency polygons for each of the following frequency distribution:
(a) using histogram
(b) without using histogram
|
C.I |
10 - 30 |
30 - 50 |
50 - 70 | 70 - 90 | 90 - 110 | 110 - 130 | 130 - 150 |
| ƒ | 4 | 7 | 5 | 9 | 5 | 6 | 4 |
Draw a histogram of the following distribution:
| Heights (in cm) | Number of students |
| 150 – 153 | 7 |
| 153 – 156 | 8 |
| 156 – 159 | 14 |
| 159 – 162 | 10 |
| 162 – 165 | 6 |
| 165 – 168 | 5 |
Following table shows a frequency distribution for the speed of cars passing through at a particular spot on a high way:
| Class interval (km/h) | Frequency |
| 30 – 40 | 3 |
| 40 – 50 | 6 |
| 50 – 60 | 25 |
| 60 – 70 | 65 |
| 70 – 80 | 50 |
| 80 – 90 | 28 |
| 90 – 100 | 14 |
Draw a histogram and frequency polygon representing the data above.
