For the following incomplete distribution of marks of 100people. Median marks is note to be 32.what is the mean mark ?
Marks No of students
0-10. 10
10-20. ?
20-30. 25
30-40. 30
40-50. ?
50-60. 10
Answers
Answer:
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Question
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Find the missing frequency in the following distribution if N=100 and median is 32
Marks
0-10
10-20
20-30
30-40
40-50
50-60
Total
No. of students
10
?
25
30
?
10
100
Easy
Solution
Correct option is A)
class f cf
0-10 10 10
10-20 x 10+x
20-30 25 35+x
30-40 30 65+x
40-50 y 65+x+y
50-60 10 75+x+y
75+x+y
75+x+y=100
x+y=25
f=30,h=10,cf=35+x,
2
n
=50
Median=l+(
f
2
n
−cf
)×h
32=(
30
50−35−x
)×10
32−30=
3
15−x
6=15−x
x=9
∴y=16