Data
unit 2: Statistical displays
Questions
2.5
1.
The mid-day temperature at a seaside holiday resort was
measured with the following results:
| Temperature
(C ) |
10
–
14
|
14
–
16
|
16
– 17
|
17
– 18
|
18
– 20
|
20
– 22
|
22
– 25
|
| Frequency |
9
|
14
|
8
|
12
|
10
|
7
|
5
|
Draw
a cumulative frequency polygon
Click
here for the answer Now
use it to estimate:
|
|
| (a)
The median temperature. |
17.1 |
| (b)
The lower quartile. |
15.0 |
| (c)
The number of days on which the temperature fell
below 19 . |
48 days |
| (d)
The temperature which was exceeded on the hottest
20 days. |
18.4 |
| (e)
The inter-quartile range. |
inter quartile range =
19.2 – 15
= 4.2 |
2.
The marks obtained by 175 students in an examination
are as follows:
| Marks |
10
– 30
|
31
–
45
|
46
– 55
|
56
–
70
|
71
–
100
|
| No.
candidates |
20
|
42
|
56
|
39
|
18
|
(a)
Find the class boundaries and proceed to draw a cumulative
frequency polygon.
Click here for the answer
| Use
your cumulative frequency polygon to find |
| (b)
The median mark |
|
| (c)
The number of students who scored between 40 and
60 marks (inclusive). |
|
| (d)
The pass mark, if 70% of the candidates passed the
exam. |
|
| |
|
