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Question
The time taken, in seconds, to solve a problem for each of 25 persons is as follows:
| 16 | 20 | 26 | 27 | 28 |
| 30 | 33 | 37 | 38 | 40 |
| 42 | 43 | 46 | 46 | 47 |
| 48 | 49 | 50 | 53 | 58 |
| 59 | 60 | 64 | 52 | 20 |
(i) Construct a frequency distribution for these data using a class interval of 10 seconds.
(ii) In a school the weekly pocket money of 50 students is as follow's:
| Weekly pocket money (₹) | No. of student |
| 40 - 50 | 2 |
| 59 - 60 | 8 |
| 60 - 70 | 12 |
| 70 - 80 | 14 |
| 80 - 90 | 8 |
| 90 - 100 | 6 |
Draw a histogram and a frequency polygon on the same graph. Find mode from the graph.
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Solution
(i) Frequency table
| Time (in seconds) |
Tally marks | Frequency |
| 10 - 20 | I | 1 |
| 20 - 30 | IIIII | 5 |
| 30 - 40 | I I I I | 4 |
| 40 - 50 | IIII I I I I | 8 |
| 50 - 60 | IIIII | 5 |
| 60 - 70 | I I | 2 |
Histogram representing the time taken in seconds, to solve. A problem for each of 25 persons.
(ii) Frequency distribution table is
| Weekly pocket money (in ₹) | Class Marks | No. of Students |
| 40 - 50 | 45 | 2 |
| 50 - 60 | 55 | 8 |
| 60 - 70 | 65 | 12 |
| 70 - 80 | 75 | 14 |
| 80 - 90 | 85 | 8 |
| 90 - 100 | 95 | 6 |
Draw the histogram and frequency polygon on the graph.
Now, in the highest rectangle, draw two straight line AB and CD from the corners of the rectangle on either sides of the highest rectangle to opposite corners of the highest rectangle. They intersect P. Draw PR X-axis, then abscissa of the point prepresents ₹ 72·5.
Hence, the required mode is ₹72·5.
RELATED QUESTIONS
Observe the following frequency polygon and write the answers of the questions below it.
- Which class has the maximum number of students?
- Write the classes having zero frequency.
- What is the class-mark of the class, having frequency of 50 students?
- Write the lower and upper class limits of the class whose class mark is 85.
- How many students are in the class 80-90?
| Electricity bill (₹) | 0 - 200 | 200 - 400 | 400 - 600 | 600 - 800 | 800 - 1000 |
| Families | 240 | 300 | 450 | 350 | 160 |
Given below is the frequency distribution of the heights of 50 students of a class:
| Class interval: | 140−145 | 145−150 | 150−155 | 155−160 | 160−165 |
| Frequency: | 8 | 12 | 18 | 10 | 5 |
Draw a histogram representing the above data.
Draw a histogram of the following data:
| Class interval: | 10−15 | 15−20 | 20−25 | 25−30 | 30−35 | 34−40 |
| Frequency: | 30 | 98 | 80 | 58 | 29 | 50 |
Number of workshops organized by a school in different areas during the last five years are as follows:
| Years | No. of workshops |
| 1995−1996 | 25 |
| 1996−1997 | 30 |
| 1997−1998 | 42 |
| 1998−1999 | 50 |
| 1999−2000 | 65 |
Draw a histogram representing the above data.
Below is the histogram depicting marks obtained by 43 students of a class:
(i) Write the number of students getting the highest marks.
(ii) What is the class size?
Identify the following data can be represented in a histogram?
Production of cycles in different years
Represent the following data by histogram:
| Price of Sugar (per kg in ₹) | Number of Weeks |
| 18 – 20 | 4 |
| 20 – 22 | 8 |
| 22 – 24 | 22 |
| 24 – 26 | 12 |
| 26 – 28 | 6 |
| 28 – 30 | 8 |
Histogram shows the number of people owning the different number of books. Answer the question based on it.
The total number of people surveyed is ______.
Show the following data by a frequency polygon:
| Electricity bill (₹) | Families |
| 200 – 400 | 240 |
| 400 – 600 | 300 |
| 600 – 800 | 450 |
| 800 – 1000 | 350 |
| 1000 – 1200 | 160 |
