Common Equations

This notebook will display equations commonly found in literature rendered via MathJax (LaTex). Please feel free to add any of your equations with a description to the repo.

Mean

Population Mean

$$ \begin{equation} \mu = {\Sigma X \over N} \end{equation} $$

\begin{verbatim} %% \begin{equation} \mu = {\Sigma X \over N} \end{equation} %% \end{verbatim}

Sample Mean

$$ \begin{equation} \bar{X} = {\Sigma X \over n} \end{equation} $$

\begin{verbatim} $$ \begin{equation} \bar{X} = {\Sigma X \over n} \end{equation} $$ \end{verbatim}

Variance

Population Variance

$$ \begin{equation} \sigma^2 = {\Sigma(X-\mu)^2 \over N} \end{equation} $$

\begin{verbatim} $$ \begin{equation} \sigma^2 = {\Sigma(X-\mu)^2 \over N} \end{equation} $$ \end{verbatim}

Sample Variance

$$ \begin{equation} s^2 = {\Sigma(X-\bar{X})^2 \over (n-1)} \end{equation} $$

\begin{verbatim} $$ \begin{equation} s^2 = {\Sigma(X-\bar{X})^2 \over (n-1)} \end{equation} $$ \end{verbatim}

Standard Deviation

Population

$$ \begin{equation} \sigma = \sqrt{\Sigma(X-\mu)^2 \over N} \end{equation} $$

\begin{verbatim} $$ \begin{equation} \sigma = \sqrt{\Sigma(X-\mu)^2 \over N} \end{equation} $$ \end{verbatim}

Sample

$$ \begin{equation} s = \sqrt{\Sigma(X-\bar{X})^2 \over (n-1)} \end{equation} $$

\begin{verbatim} $$ \begin{equation} s = \sqrt{\Sigma(X-\bar{X})^2 \over (n-1)} \end{equation} $$ \end{verbatim}

Covariance

Sample

$$ \begin{equation} cov(x,y) = {\Sigma(x-\bar{x})(y-\bar{y}) \over (n-1)} \end{equation} $$

\begin{verbatim} $$ \begin{equation} cov(x,y) = {\Sigma(x-\bar{x})(y-\bar{y}) \over (n-1)} \end{equation} $$ \end{verbatim}

Population

$$ \begin{equation} cov(x,y) = {\Sigma(x-\mu_{x})(y-\mu_{y}) \over N} \end{equation} $$

\begin{verbatim} $$ \begin{equation} cov(x,y) = {\Sigma(x-\mu_{x})(y-\mu_{y}) \over N} \end{equation} $$ \end{verbatim}

Pearson Correlation

Sample

$$ \begin{equation} r = {\Sigma(z_{x}z_{y}) \over (n-1)} \end{equation} $$

\begin{verbatim} $$ \begin{equation} \rho = {\Sigma(z_{x}z_{y}) \over (n-1)} \end{equation} $$ \end{verbatim}

Population

$$ \begin{equation} \rho = {\Sigma(z_{x}z_{y}) \over N} \end{equation} $$

\begin{verbatim} $$ \begin{equation} \rho = {\Sigma(z_{x}z_{y}) \over N} \end{equation} $$ \end{verbatim}

Information Entropy

$$ H(X)=-\sum _{i=1}^{n}p(x_{i})\log p(x_{i}) $$

\begin{verbatim} $$ H(X)=-\sum _{i=1}^{n}p(x_{i})\log p(x_{i}) $$ \end{verbatim}

Softmax

$$ P(y=j|\mathbf {x} )={\frac {e^{\mathbf {x} ^{\mathsf {T}}\mathbf {w} _{j}}}{\sum _{k=1}^{K}e^{\mathbf {x} ^{\mathsf {T}}\mathbf {w} _{k}}}} $$

\begin{verbatim} $$ P(y=j|\mathbf {x} )={\frac {e^{\mathbf {x} ^{\mathsf {T}}\mathbf {w} _{j}}}{\sum _{k=1}^{K}e^{\mathbf {x} ^{\mathsf {T}}\mathbf {w} _{k}}}} $$ \end{verbatim}

Jeffreys Prior

$$ \left({\vec \theta }\right)\propto {\sqrt {\det {\mathcal {I}}\left({\vec \theta }\right)}}.\ $$

\begin{verbatim} $$ \left({\vec \theta }\right)\propto {\sqrt {\det {\mathcal {I}}\left({\vec \theta }\right)}}.\ $$ \end{verbatim}

z Score

Population $$ \begin{equation} z = {X-\mu \over \sigma} \end{equation} $$

\begin{verbatim} \begin{equation} z = {X-\mu \over \sigma} \end{equation} \end{verbatim}

Sample \begin{equation} z = {X-\bar{X} \over s} \end{equation}

\begin{verbatim} \begin{equation} z = {X-\bar{X} \over s} \end{equation} \end{verbatim}