4. Represent
the following data using histogram and hence draw frequency polygon:
|
No. of words
typed per minute
|
30 – 39
|
40 – 49
|
50 – 59
|
60 – 69
|
70 – 79
|
|
No. of
typists
|
2
|
8
|
15
|
12
|
3
|
Solution:
|
No of words
typed per minute
(Class
interval)
|
Extended
Class
|
No. of
typists
|
|
20 - 29
|
19.5 – 29.5
|
0
|
|
30 – 39
|
29.5 – 39.5
|
2
|
|
40 – 49
|
39.5 – 49.5
|
8
|
|
50 – 59
|
49.5 – 59.5
|
15
|
|
60 – 69
|
59.5 – 69.5
|
12
|
|
70 – 79
|
69.5 – 79.5
|
3
|
|
80 – 89
|
79.5 – 89.5
|
0
|
