Using Step deviation method ,Calculate the standard Deviation of the following Series
Series Frequency
0-10 5
10-20 10
20-30 20
30-40 40
40-50 30
50-60 20

Question

Using Step deviation method ,Calculate the standard Deviation of
the following Series
Series Frequency
0-10 5
10-20 10
20-30 20
30-40 40
40-50 30
50-60 20

Mehak Garg · Accepted Answer

Dear Student,

Standard Deviation in Continuous Series

Series
Mid Values (m)
Frequency (f)
d=X-A
d'=d2C; C=10
fd'
fd'2

0-10
5
5
-30
-3
-15
45

10-20
15
10
-20
-2
-20
40

20-30
25
20
-10
-1
-20
20

30-40
35 (Let A)
40
0
0
0

40-50
45
30
10
1
30
30

50-60
55
20
20
2
40
80

N = 125

∑fd' = 15
∑fd'2 =215

S D = ∑fd'2N-(∑fd'N)2 × C =
215125-(15125)2 × 10 = 13 07
Regards

Series	Mid Values (m)	Frequency (f)	d=X-A	d'= $\frac{d^{2}}{C}$ ; C=10	fd'	f $d'^{2}$
0-10	5	5	-30	-3	-15	45
10-20	15	10	-20	-2	-20	40
20-30	25	20	-10	-1	-20	20
30-40	35 (Let A)	40	0	0	0
40-50	45	30	10	1	30	30
50-60	55	20	20	2	40	80
		N = 125			$\sum_{}^{} f d' =$ 15	$\sum_{}^{} f d'^{2} =$ 215

Using Step deviation method ,Calculate the standard Deviation of the following Series Series Frequency 0-10 5 10-20 10 20-30 20 30-40 40 40-50 30 50-60 20

Using Step deviation method ,Calculate the standard Deviation of the following Series
Series Frequency
0-10 5
10-20 10
20-30 20
30-40 40
40-50 30
50-60 20