The standard deviation (σ) is a measure of spread in statistics. It is calcualted by taking the square root of the variance, which is itself the average of the square of difference of values from their arithmetic mean. The standard deviation of a simple set of N numbers xi with mean μ is:
σ = √ ( Σ (xi− μ)2 / N )
σ = √ ( Σ (xi− μ)2 / N )
Used in Chap. 7: pages 93, 95; Chap. 8: page 109; Chap. 10: pages 137, 138; Chap. 12: page 170
Links:
alandix.com: standard deviation (s.d., σ)