Calculate the mean, variance and standard deviation for the following distribution :-
Marks : above 30&below 40 below 50 below 60 below 70 below 80 below 90 below 100
No. of Students :3 10 22 37 45 48 50

Question

​Calculate the mean, variance and standard deviation for the
following distribution :-
Marks : above 30&below 40 below 50 below 60 below 70 below 80
below 90 below 100
No of Students :3 10 22 37 45 48 50

Neha Sethi · Accepted Answer

Dear student

Marks
Number of students
xi
di=xi-A
ui=di/h
fiui

30-40
3
35
-30
-3
-9

40-50
7
45
-20
-2
-14

50-60
12
55
-10
-1
-12

60-70
15
65
0
0
0

70-80
8
75
10
1
8

80-90
3
85
20
2
6

90-100
2
95
30
3
6

N=50

∑fiui=-15

Mean=A+h1N∑fiui=65+10-1550=65-3=62
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Marks	Number of students	$x_{i}$	d_i=x_i-A	u_i=d_i/h	f_iu_i
30-40	3	35	-30	-3	-9
40-50	7	45	-20	-2	-14
50-60	12	55	-10	-1	-12
60-70	15	65	0	0	0
70-80	8	75	10	1	8
80-90	3	85	20	2	6
90-100	2	95	30	3	6
	N=50				$\sum_{}^{} f_{i} u_{i} =$ -15

​Calculate the mean, variance and standard deviation for the following distribution :- Marks : above 30&below 40 below 50 below 60 below 70 below 80 below 90 below 100 No. of Students :3 10 22 37 45 48 50

Calculate the mean, variance and standard deviation for the following distribution :-
Marks : above 30&below 40 below 50 below 60 below 70 below 80 below 90 below 100
No. of Students :3 10 22 37 45 48 50