Question

Five body weights (in grams) collected from a population of rodents are 66.1, 77.1, 74.6, 61.8, 71.5 What is the sample standard deviation (round to 2-decimals)?

Answer 1

The given sample data is
x = [66.1,77.1,74.6,61.8,71.5]
The sample size is n = 5.

Calculate the mean value.
m = (66.1+77.1+74.6+61.8+71.5)/5 = 70.22

Calculate the array (x - m).
x-m = [-4.12, 6.88, 4.38, -8.42, 1.28]
Calculate (x-m)².
(x-m)² = [16.9744, 47.3344, 19.1844, 70.8964, 1.6384]

Calculate the standard deviation

`s= \sqrt{ (\sum(x-m)^(2))/(n-1) } = \sqrt{ (156.028)/(4) } =6.2456`

Answer: The standard deviation is 6.25 (to 2 decimal places)