Tools
Intervals & Tests
Hypothesis Test Of Sample Mean Example
Hypothesis Test Of Two Sample Variances Example
Hypothesis Test Of A Standard Deviation Compared To A Standard Value Example
Distributions
Area Under the Standard Normal Curve
Non-Normal Distributions in the Real World
Rayleigh Distribution for True Position
Skewness
What is skewness? It is a measure of the symmetry of a distribution around its mean. Positive values indicate a shift or tail to the right; negative values indicate a shift or tail to the left. Skewness is 0 for a normal distribution. To calculate, use the skewness formula below.
where xj is the observation j, N is the total number of observations, x-doublebar is the Average, and σx is the Sample Sigma.
Learn more about the Statistical Inference tools for understanding statistics in Six Sigma Demystified (2011, McGraw-Hill) by Paul Keller, in his online Intro. to Statistics short course (only $89) or his online Black Belt certification training course ($875).
