σ = Σ ( x − μ ) 2 N {\displaystyle \sigma ={{\Sigma \left(x-\mu \right)^{2}} \over N}}
S = Σ ( x − x ¯ ) 2 N − 1 {\displaystyle S={{\Sigma \left(x-{\bar {x}}\right)^{2}} \over {N-1}}}
Z = x − μ σ {\displaystyle Z={{x-\mu } \over \sigma }}
Z = x − x ¯ S {\displaystyle Z={{x-{\bar {x}}} \over S}}
Z x ¯ = x ¯ − μ σ N = N ( x ¯ − μ ) σ {\displaystyle Z_{\bar {x}}={{{\bar {x}}-\mu } \over {\sigma \over {\sqrt {N}}}}={{{\sqrt {N}}\left({\bar {x}}-\mu \right)} \over \sigma }}
