Advertisements
Advertisements
Question
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 |
Advertisements
Solution
| Marks | No. of students (f) | Cumulative frequency |
| 25 | 6 | 6 |
| 30 | 15 | 21 |
| 35 | 12 | 33 |
| 40 | 10 | 43 |
| 45 | 18 | 61 |
| 50 | 9 | 70 |
No. of terms = 70
Lower Quartile (Q1) = `n/4 = 70/4` = 17.5th term = 30
Upper Quartile (Q3) = `(n xx 3)/4 = (70 xx 3)/4` = 52.5th term = 45
Interquartile range = Q3 - Q1 = 45-30 = 15
Semi-Interquartile range = `(Q_3 - Q_1)/2 = (45-30)/2 = 7.5`
Hence, Lower quartile = 30, upper quartile = 45, interquartile range = 15, semi -interquartile range = 7.5
APPEARS IN
RELATED QUESTIONS
Represent the following data by Histogram:
|
Price of Sugar per kg (in Rs.) |
Number of Weeks |
| 18-20 | 4 |
| 20-22 | 8 |
| 22-24 | 22 |
| 24-26 | 12 |
| 26-28 | 8 |
| 28-30 | 6 |
Draw histogram for the following frequency distributions:
| Class Interval | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 |
| Frequency | 12 | 20 | 26 | 18 | 10 | 6 |
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?
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.
Construct histograms for following frequency distribution:
| Class Mark | 15 | 25 | 35 | 45 | 50 | 55 | 60 |
| Frenuencv | 6 | 12 | 15 | 18 | 25 | 14 | 10 |
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 |
The graphical representation of ungrouped data is ________
The following pictorial representation of data is a histogram.
The following histogram shows the frequency distribution of teaching experiences of 30 teachers in various schools:
- What is the class width?
- How many teachers are having the maximum teaching experience and how many have the least teaching experience?
- How many teachers have teaching experience of 10 to 20 years?
Use graph paper for this question. Estimate the mode of the given distribution by plotting a histogram. [Take 2 cm = 10 marks along one axis and 2 cm = 5 students along the other axis]
| Daily wages (in ₹) | 30 - 40 | 40 - 50 | 50 - 60 | 60 - 70 | 70 - 80 |
| No. of Workers | 6 | 12 | 20 | 15 | 9 |
