Page 8 - Lesson note- 2- Ch 14 Statistics (Frequency Distribution)
P. 8
(i)
Hours No of children
0-5 10
5-10 13
10-15 5
15-20 2
Total 30
(ii)The number of children who watched TV for 15 or more hours a week is 2 (i.e. the
number of children in class interval 15 − 20).
Example- 8.
A company manufactures car batteries of a particular type. The lives (in years) of 40
such batteries were recorded as follows: 2.6 3.0 3.7 3.2 2.2 4.1 3.5 4.5 3.5 2.3 3.2 3.4
3.8 3.2 4.6 3.7 2.5 4.4 3.4 3.3 2.9 3.0 4.3 2.8 3.5 3.2 3.9 3.2 3.2 3.1 3.7 3.4 4.6 3.8 3.2
2.6 3.5 4.2 2.9 3.6
Construct a grouped frequency distribution table for this data, using class intervals of
size 0.5 starting from the intervals 2 − 2.5.
Solution:
A grouped frequency table of class size 0.5 has to be constructed, starting from class
interval 2 − 2.5. Therefore, the class intervals will be 2 − 2.5, 2.5 − 3, 3 − 3.5… By
observing the data given above, the required grouped frequency distribution table can
be constructed as follows.
