Advertisements
Advertisements
Question
Construct a frequency polygon without using a histogram for the following frequency distribution :
| Class Interval | 1-10 | 11-20 | 21-30 | 31-40 | 41-50 |
| Frequency | 8 | 12 | 10 | 16 | 6 |
Advertisements
Solution
Steps :
1. Make the class intervals continuous by subtracting 0.5 from the lower limit of each class and add 0.5 to the upper limit of each class .
2. Find class mark by calculating the average of the class interval.
3. On the x-axis , take 1 cm as 5 units and plot class interval.
4. On the y-axis , take 1 cm as 5 units and plot frequency.
5. Plot the points on the graph. (5.5,8),(15.5,12),(25.5,10),(35.5,16),(45.5,6).
6. Mark two more midpoints of zero frequency on x-axis at the start and at the end.
7. Now connect the points using straight lines.
| Class Interval | Class Mark | Frequency |
| 0.5-10.5 | = `(0.5+10.5)/2 = 5.5` | 8 |
| 10.5-20.5 | = `(10.5+20.5)/2 = 15.5` | 12 |
| 20.5-30.5 | = `(20.5 + 30.5)/2 = 25.5` | 10 |
| 30.5-40.5 | = `(30.5 + 40.5)/2 = 35.5` | 16 |
| 40.5-50.5 | = `(40.5 + 50.5)/2 = 45.5` | 6 |
APPEARS IN
RELATED QUESTIONS
The table below shows the yield of jowar per acre. Show the data by histogram.
| Yield per acre (quintal) | 2 - 3 | 4 - 5 | 6 - 7 | 8 - 9 | 10 - 11 |
| No. of farmers | 30 | 50 | 55 | 40 | 20 |
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 |
The following histogram shows the number of literate females in the age group of 10 to 40 years in a town:
(i) Write the age group in which the number of literate female is the highest.
(ii) What is the class width?
(iii) What is the lowest frequency?
(iv) What are the class marks of the classes?
(v) In which age group literate females are the least?
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?
Find the lower quartile, the upper quartile, the interquartile range and the semi-interquartile range for the following frequency distributions:
| Marks | 25 | 30 | 35 | 40 | 45 | 50 |
| No. of students | 6 | 15 | 12 | 10 | 18 | 9 |
Construct histograms for following frequency distribution:
| Class Mark | 15 | 25 | 35 | 45 | 50 | 55 | 60 |
| Frenuencv | 6 | 12 | 15 | 18 | 25 | 14 | 10 |
Construct histograms for following frequency distribution:
| Class Interval | 110-119 | 120-129 | 130-139 | 140-149 | 150-159 |
| Frequency | 15 | 23 | 30 | 20 | 16 |
Following table present educational level (middle stage) of females in Arunachal pradesh according to 1981 census:
| Age group | Number of females (to the nearest ten) |
| 10 - 14 | 300 |
| 15 - 19 | 980 |
| 20 - 24 | 800 |
| 25 - 29 | 380 |
| 30 - 34 | 290 |
Draw a histogram to represent the above data.
Histogram shows the number of people owning the different number of books. Answer the question based on it.
The number of people having books more than 20 and less than 40 is ______.
Prepare a histogram from the frequency distribution table obtained in question 93.
