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प्रश्न
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 the frequency polygon representing the above data without drawing the histogram.
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उत्तर
First we obtain in the class marks (mid-marks) of the given table as:
Class-marks = `("Lower limit" + "Upper limit")/2`
Since, the new table is shown below:
| Class interval | Class marks | Frequency |
| 30 – 40 | 35 | 3 |
| 40 – 50 | 45 | 6 |
| 50 – 60 | 55 | 25 |
| 60 – 70 | 65 | 65 |
| 70 – 80 | 75 | 50 |
| 80 – 90 | 85 | 28 |
| 90 – 100 | 95 | 14 |
Now, let’s draw a frequency polygon by plotting the class marks along the x-axis and the frequency along y-axis.
Also, plotting all the points as B(35, 3), C(45, 6), (D(55, 25), E(65, 65), F(75, 50), G(85, 28) and H(95, 14).
Then join all these point line segment, shown below:

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संबंधित प्रश्न
100 surnames were randomly picked up from a local telephone directory and a frequency distribution of the number of letters in the English alphabet in the surnames was found as follows:
| Number of letters | Number of surnames |
| 1 - 4 | 6 |
| 4 - 6 | 30 |
| 6 - 8 | 44 |
| 8 - 12 | 16 |
| 12 - 20 | 4 |
- Draw a histogram to depict the given information.
- Write the class interval in which the maximum number of surnames lie.
Study the bar graph representing the number of persons in various age groups in a town shown in Fig. below. Observe the bar graph and answer the following questions:
(i) What is the percentage of the youngest age-group persons over those in the oldest age group?
(ii) What is the total population of the town?
(iii) What is the number of persons in the age group 60 - 65?
(iv) How many persons are more in the age-group 10 - 15 than in the age group 30 - 35?
(v) What is the age-group of exactly 1200 persons living in the town?
(vi) What is the total number of persons living in the town in the age-group 50 - 55?
(vii) What is the total number of persons living in the town in the age-groups 10 - 15 and 60 - 65?

(viii) Whether the population in general increases, decreases or remains constant with the increase in the age-group.
Given below (Fig. below) is the bar graph indicating the marks obtained out of 50 in mathematics paper by 100 students. Read the bar graph and answer the following questions:

(i) It is decided to distribute work books on mathematics to the students obtaining less than 20 marks, giving one workbook to each of such students. If a work book
costs Rs 5, what sum is required to buy the work books?
(ii) Every student belonging to the highest mark group is entitled to get a prize of Rs. 10. How much amount of money is required for distributing the prize money?
(iii) Every student belonging to the lowest mark—group has to solve 5 problems per day. How many problems, in all, will be solved by the students of this group per day?
(iv) State whether true or false.
a. 17% students have obtained marks ranging from 40 to 49.
b. 59 students have obtained marks ranging from 10 to 29.
(v) What is the number of students getting less than 20 marks?
(vi) What is the number of students getting more than 29 marks?
(vii) What is the number of students getting marks between 9 and 40?
(viii) What is the number of students belonging to the highest mark group?
(ix) What is the number of students obtaining more than 19 marks?
Read the following bar graph(Fig. 23.15) and answer the following questions:
(i) What information is given by the bar graph?
(ii) What was the production of a student in the year 1980 - 81?
(iii) What is the minimum and maximum productions of cement and corresponding years?

Read the bar graph given in Fig. below and answer the following questions:

(i) What information does it give?
(ii) In which part the expenditure on education is maximum in 1980?
(iii) In which part the expenditure has gone up from 1980 to 1990?
(iv) In which part the gap between 1980 and 1990 is maximum?
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 number (in thousands) of applicants registered with an
| Year | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 |
| Number of applicants registered (in thousands) | 18 | 20 | 24 | 28 | 30 | 34 |
Construct a bar graph to represent the above data.

The following table gives the route length (in thousand kilometres) of the Indian Railways in some of the years:
| Year | 1960-61 | 1970-71 | 1980-81 | 1990-91 | 2000-2001 |
| Route length (in thousand km) |
56 | 60 | 61 | 74 | 98 |
Represent the above data with the help of a bar graph.
The following is the distribution of total household expenditure (in Rs.) of manual worker in a city:
| Expenditure (in Rs): |
100-150 | 150-200 | 200-250 | 250-300 | 300-350 | 350-400 | 400-450 | 450-500 |
| No. of manual workers: | 25 | 40 | 33 | 28 | 30 | 22 | 16 | 8 |
Draw a histogram and a frequency polygon representing the above data.
Construct a frequency polygon for the following data:
| Class-Intervals | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 |
| Frequency | 5 | 8 | 12 | 9 | 4 |
