Question

The following data gives the

information on the observed life
Span (in hours) of 90 Electrical components
Life Span 0-20 20-40/40-60 60-80/80-00/100-120
frequency Is
8,12,15,23,18,14
Draw both o gives the above data
​

Answer 1

Answer:

Lifetime

(in hours) No. of components

0-20 10

20-40 35

40-60 52

60-80 61

80-100 38

100-120 29

As frequency is maximum for the class 60−80, modal class is 60−80.

Mode=l+

2f

1

−(f

0

+f

2

)

f

1

−f

0

×h

where,

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 succeding the modal class =38

h= higher limit - lower limit =80−60=20

Mode=60+

2×61−(52+38)

61−52

×20

⇒mode=60+

32

9

×20=60+5.625=65.625