Question

An expert reviews a sample of 10 scientific articles (n = 10) and records the following number of errors in each article: 9, 7, 0, 1, 4, 7, 6, 8, 0, and 3. Compute SS, variance, and standard deviation for this sample using the definitional and computational formula. (Round your answers to two decimal places.)

SS

variance

standard deviation

Answer 1

Sample mean = X / n = 4.5

a)

SS = ( Xi - )²

= = (9 - 4.5)² + (7 - 4.5)² + (0 - 4.5)² + (1 - 4.5)² + (4 - 4.5)² + (7 - 4.5)² + (6 - 4.5)² + (8 - 4.5)² + (0 - 4.5)² + (3 - 4.5)²

= 102.5

b)

Variance = SS / ( n -1)

= 102.5 / ( 10 - 1)

= 11.39

c)

Standard deviation = sqrt ( Variance)

= sqrt ( 11.39)

= 3.37