Statistics
Exercise 14.3
Part 2
Question 4: The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table:
| Length (in mm) | Number of Leaves |
|---|---|
| 118 – 126 | 3 |
| 127 – 135 | 5 |
| 136 – 144 | 9 |
| 145 – 153 | 12 |
| 154 – 162 | 5 |
| 163 – 171 | 4 |
| 172 – 180 | 2 |
(i) Draw a histogram to represent the given data.
Answer:
(ii) Is there any other suitable graphical representation for the same data?
Answer: Frequency Polygon
(iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?
Answer: No, because the data in a particular row shows a range rather than a single number.
Question 5: The following table gives the life times of 400 neon lamps:
| Life Time (in hours) | Number of Lamps |
|---|---|
| 300 – 400 | 14 |
| 400 – 500 | 56 |
| 500 – 600 | 60 |
| 600 – 700 | 86 |
| 700 – 800 | 74 |
| 800 – 900 | 62 |
| 900 – 1000 | 48 |
(i) Represent the given information with the help of a histogram.
Answer:
(ii) How many lamps have a life time of more than 700 hours?
Answer: 184
Question 6: The following table gives the distribution of students of two sections according to the marks obtained by them:
| Section A | Section B | ||
|---|---|---|---|
| Marks | Frequency | Marks | Frequency |
| 0 – 10 | 3 | 0 – 10 | 5 |
| 10 – 20 | 9 | 10 – 20 | 19 |
| 20 – 30 | 17 | 20 – 30 | 15 |
| 30 – 40 | 12 | 30 – 40 | 10 |
| 40 – 50 | 9 | 40 – 50 | 1 |
Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.
Answer:
