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प्रश्न
The following table gives the distribution of IQ's (intelligence quotients) of 60 pupils of class V in a school:
| IQ's: | 125.5 to 13.25 |
118.5 to 125.5 |
111.5 to 118.5 |
104.5 to 111.5 |
97.5 to 104.5 |
90.5 to 97.5 |
83.5 to 90.5 |
76.5 to 83.5 |
69.5 to 76.5 |
62.5 to 69.5 |
| No. of pupils: |
1 | 3 | 4 | 6 | 10 | 12 | 15 | 5 | 3 | 1 |
Draw a frequency polygon for the above data.
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उत्तर १
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 given data is a continuous grouped frequency distribution with equal class-intervals. To draw the frequency polygon of the given data without using histogram, obtain the class-limits of the class intervals. Obtain the class-limits of two class-intervals of 0 frequencies, i.e. on the horizontal axis, one adjacent to the first, on its left and one adjacent to the last, on its right. These class-intervals are known as imagined class-intervals. Then plot the frequencies against class-limits.
The following table is useful to draw the frequency polygon of the given data.
| Class - Intervals | Class - Marks | Frequency |
| 55.5-62.5 | 59 | 0 |
| 62.5-69.5 | ||
We represent class marks on X-axis on a suitable scale and the frequencies on Y-axis on a suitable scale.
To obtain the frequency polygon we plot the points (66, 1), (73, 3), (80, 5), (87, 15), (94, 12), (101, 10), (108, 6), (115, 4), (122, 3), (129, 1).
Now we join the plotted points by line segments. The end points (66, 1) and (129, 1) are joined to the mid points (59, 0) and ( 136, 0) respectively of imagined class intervals to obtain the frequency polygon.
उत्तर २
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 given data is a continuous grouped frequency distribution with equal class-intervals. To draw the frequency polygon of the given data without using histogram, obtain the class-limits of the class intervals. Obtain the class-limits of two class-intervals of 0 frequencies, i.e. on the horizontal axis, one adjacent to the first, on its left and one adjacent to the last, on its right. These class-intervals are known as imagined class-intervals. Then plot the frequencies against class-limits.
The following table is useful to draw the frequency polygon of the given data.
| Class - Intervals | Class - Marks | Frequency |
| 55.5-62.5 | 59 | 0 |
| 62.5-69.5 | 66 | 1 |
| 69.5 - 76.5 | 73 | 3 |
| 76.5 - 83.5 | 80 | 5 |
| 83.5 - 90.5 | 87 | 15 |
| 90.5 - 97.5 | 94 | 12 |
| 97.5-104.5 | 101 | 10 |
| 104-111.5 | 108 | 6 |
| 111.5 - 118.5 | 115 | 4 |
| 118.5-125.5 | 122 | 3 |
| 125.5-132.5 | 129 | 1 |
| 132.5-139.5 | 136 | 0 |
We represent class marks on X-axis on a suitable scale and the frequencies on Y-axis on a suitable scale.
To obtain the frequency polygon we plot the points (66, 1), (73, 3), (80, 5), (87, 15), (94, 12), (101, 10), (108, 6), (115, 4), (122, 3), (129, 1).
Now we join the plotted points by line segments. The end points (66, 1) and (129, 1) are joined to the mid points (59, 0) and ( 136, 0) respectively of imagined class intervals to obtain the frequency polygon.
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संबंधित प्रश्न
A survey conducted by an organisation for the cause of illness and death among the women between the ages 15 - 44 (in years) worldwide, found the following figures (in %):-
| S.No. | Causes | Female fatality rate (%) |
| 1. | Reproductive health conditions | 31.8 |
| 2. | Neuropsychiatric conditions | 25.4 |
| 3. | Injuries | 12.4 |
| 4. | Cardiovascular conditions | 4.3 |
| 5. | Respiratory conditions | 4.1 |
| 6. | Other causes | 22.0 |
- Represent the information given above graphically.
- Which condition is the major cause of women’s ill health and death worldwide?
- Try to find out, with the help of your teacher, any two factors which play a major role in the cause in (ii) above being the major cause.
Read the following bar graph (Fig. 23.12) and answer the following questions:
(i) What is the information given by the bar graph?
(ii) State each of the following whether true or false.
a. The number of government companies in 1957 is that of 1982 is 1 :9.
b. The number of government companies have decreased over the year 1957 to 1983.
Read the bar graph given in Fig. 23.21 and answer the following questions:
(i) What is the information given by the bar graph?
(ii) What is the number of families having 6 members?
(iii) How many members per family are there in the maximum number of families? Also tell the number of such families.
(iv) What are the number of members per family for which the number of families are equal? Also, tell the number of such families?
The production of saleable steel in some of the steel plants our country during 1999 is given below:
| Plant | Bhilai | Durgapur | Rourkela | Bokaro |
| Production (In thousand tonnes) |
160 | 80 | 200 | 150 |
Construct a bar graph to represent the above data on a graph paper by using the scale 1 big divisions = 20 thousand tonnes.
The following table shows the interest paid by a company (in lakhs):
| Year | 1995-96 | 1996-97 | 1997-98 | 1998-99 | 1999-2000 |
| Interest (in lakhs of rupees | 20 | 25 | 15 | 18 | 30 |
Draw the bar graph to represent the above information.
The expenditure (in 10 crores of rupees) on health by the Government of India during the various five year plans is shown below:
| Plans: | I | II | III | IV | V | VI |
| Expenditure on health (in 10 crores of rupees) |
7 | 14 | 23 | 34 | 76 | 182 |
Construct a bar graph to represent the above data.
In the 'less than' type of ogive the cumulative frequency is plotted against
The daily wages in a factory are distributed as follows:
|
Daily wages (in Rs.) |
125 - 175 |
175 - 225 |
225 - 275 |
275 - 325 |
325 - 375 |
|
Number of workers |
4 |
20 |
22 |
10 |
6 |
Draw a frequency polygon for this distribution.
The expenditure of a family on different heads in a month is given below:
| Head | Food | Education | Clothing | House Rent | Others | Savings |
| Expenditure (in Rs) |
4000 | 2500 | 1000 | 3500 | 2500 | 1500 |
Draw a bar graph to represent the data above.
Following table gives the distribution of students of sections A and B of a class according to the marks obtained by them.
| Section A | Section B | ||
| Marks | Frequency | Marks | Frequency |
| 0 – 15 | 5 | 0 – 15 | 3 |
| 15 – 30 | 12 | 15 – 30 | 16 |
| 30 – 45 | 28 | 30 – 45 | 25 |
| 45 – 60 | 30 | 45 – 60 | 27 |
| 60 –75 | 35 | 60 – 75 | 40 |
| 75 – 90 | 13 | 75 – 90 | 10 |
Represent the marks of the students of both the sections on the same graph by two frequency polygons. What do you observe?
