The Highest Class Interval (HCI) is 135 – 139 and the class frequencies from the Lowest Class Interval (LCI) are 2, 5, 8, 12, 10, & 3. What is the class frequency of the modal class?
Answers
Answer:
65.625 hours
Step-by-step explanation:
search-icon-header
Search for questions & chapters
search-icon-image
Question
Bookmark
The following data gives the information on the observed lifetimes (in hours) of 225 electrical components:
Lifetimes (in hours)
0−20
20−40
40−60
60−80
80−100
100−120
Frequency
10
35
52
61
38
29
Determine the modal lifetimes of the components.
Medium
Solution
verified
Verified by Toppr
Here , frequency of class interval 60−80 is maximum.
So, it is the modal class
Now, l= Lower limit of modal class =60
f
1
= Frequency of modal class =61
f
0
= Frequency of class preceding the modal class =52
f
2
= Frequency of class succeeding the modal class =38
h= Class interval width = 20
So, Mode =l+(
2f
1
−f
0
−f
2
f
1
−f
0
)×h
=60+(
2(61)−52−38
61−52
)×20
=60+(
122−90
9
)×20
=60+(
32
9
)×20
=60+5.625
Mode =65.625
Therefore, modal lifetime of electrical components is 65.625 hours