12. Find the inode of the following distribution of marks obtained fo
by students in an examination
0-20
20-40
40-60
60-80
80-100
Marks
obtained
No. of
students
15
18.
21
29
17
Answers
Answered by
0
Answer:
Marks obtained Number of students
0−20 15
20−40 18
40−60 21
60−80 29
80−100 17
Here,
modal class : 60−80
lower limit of the modal class l=60
h= size of class interval =20
f
0
= frequency of the class just before the modal class =21
f
1
= frequency of the modal class =29
f
2
= frequency of the class just after the modal class =17
Mode =l+
2f
1
−f
0
−f
2
f
1
−f
0
×h=60+
58−21−17
29−21
×20=60+
20
160
=68
∴ Mode, Mean =53
Mean, median and mode are related by the following empirical relationship :
Mean- Mode =3 ( Mean- Median)
OR
3-Median =2× Mean+Mode
∴ Median =
3
Mode+2×Mean
=
3
68+2×53
=59
∴ Median =59
Similar questions