Question

Given here are a set of sample data: 12.0, 18.3, 29.6, 14.3, and 27.8. the sample standard deviation for this data is equal to _____.

Answer 1

The answer is 7.9306

Using the formula in the attached:
Where: xi = sample value; μ = sample mean; n = sample size

1.) Calculate the mean first:
μ = 12.0 + 18.3 + 29.6 + 14.3 + 27.8 / 5
= 102 / 5
μ = 20.4

2.) Using the mean, calculate (xi - μ)² for each value:
(12.0 - 20.4)² = 70.56
(18.3 - 20.4)² = 4.41
(29.6 - 20.4)² = 84.64
(14.3 - 20.4)² = 37.21
(27.8 - 20.4)² = 54.76

3.) Sum the squared differences and divide by n - 1.
μ = 70.56 + 4.41 + 84.64 + 37.21 + 54.76
= 251.58 / 5-1
μ = 62.895 (this is now called sample variance)

4.) Get the square root of the sample variance:
√62.895 = 7.9306