Question

An expert reviews a sample of 10 scientific articles (n = 10) and records the following number of errors in each article: 4, 6, 3, 5, 2, 8, 4, 7, 1, and 4. Compute SS, variance, and standard deviation for this sample using the definitional and computational formula. (Round your answers to two decimal places.)

Answer 1

(a)

Definitional Formula of Variance::

Mean = is calculated as follows:

x	x -	(x - )2
4	- 0.4	0.16
6	1.6	2.56
3	- 1.4	1.96
5	0.6	0.36
2	- 2.4	5.76
8	3.6	12.96
4	- 0.4	0.16
7	2.6	6.76
1	- 3.4	11.56
4	- 0.4	0.16
Total =		42.4

So,

SS = Sum of Squares = 42.40

Variance (s²) is given by:

Standard deviation (s) is given by:

s =

(b)

Computational Formula for Variance:

x	x2
4	16
6	36
3	9
5	25
2	4
8	64
4	16
7	49
1	1
4	16
Total = 44	236

So,

Variance (s²) is given by:

Standard deviation (s) is given by:

s =