\documentclass[10pt]{article} %\usepackage{amsbsy} % for \boldsymbol and \pmb %\usepackage{graphicx} % To include pdf files! \usepackage{amsmath} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{euscript} % for \EuScript \usepackage[colorlinks=true, pdfstartview=FitV, linkcolor=blue, citecolor=blue, urlcolor=blue]{hyperref} % For links \oddsidemargin=-.25in % Good for US Letter paper \evensidemargin=0in \textwidth=6.3in \topmargin=-0.7in \headheight=0.1in \headsep=0.1in \textheight=9.4in \pagestyle{empty} % No page numbers \begin{document} \enlargethispage*{1000 pt} \begin{center} {\Large \textbf{STA 302 Formulas}}\\ % Version 2 \vspace{1 mm} \end{center} % Spectral decomposition, linear independence. % MGFs % Random vectors % Linear model % Distribution facts, incl x2 addup? % Test stats and CIs \noindent \renewcommand{\arraystretch}{2.0} \begin{tabular}{lll} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Univariate MGF %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% $M_y(t) = E(e^{yt})$ & ~~~~~ & $M_{ay}(t) = M_y(at)$ \\ $M_{y+a}(t) = e^{at}M_y(t)$ & ~~~~~ & $M_{_{\sum_{i=1}^n y_i}}(t) = \prod_{i=1}^n M_{y_i}(t)$ \\ $y \sim N(\mu,\sigma^2)$ means $M_{_y}(t) = e^{\mu t + \frac{1}{2}\sigma^2t^2}$ & ~~~~~ & $y \sim \chi^2(\nu)$ means $M_{_y}(t) = (1-2t)^{-\nu/2}$ \\ \multicolumn{3}{l}{If $w=w_1+w_2$ with $w_1$ and $w_2$ independent, $w\sim\chi^2(\nu_1+\nu_2)$, $w_2\sim\chi^2(\nu_2)$ then $w_1\sim\chi^2(\nu_1)$} \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Simple regression %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% $y_i = \beta_0 + \beta_1 x_i + \epsilon_i$ & ~~~~~ & $b_0 = \overline{y} - b_1\overline{x}$ \\ $b_1 = \frac{\sum_{i=1}^n(x_i-\overline{x})(y_i-\overline{y})} {\sum_{i=1}^n(x_i-\overline{x})^2} = \frac{\sum_{i=1}^n x_iy_i - n \, \overline{x} \, \overline{y}} {\sum_{i=1}^n x_i^2 - n\overline{x}^2}$ & ~~~~~ & $r = \frac{\sum_{i=1}^n (x_i-\overline{x})(y_i-\overline{y})} {\sqrt{\sum_{i=1}^n (x_i-\overline{x})^2} \sqrt{\sum_{i=1}^n (y_i-\overline{y})^2}}$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Linear algebra %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \parbox{7 cm}{Columns of $A$ \emph{linearly dependent} means there is a vector $\mathbf{v} \neq \mathbf{0}$ with $A\mathbf{v} = \mathbf{0}$.} & ~~~~~ & \parbox{7 cm}{Columns of $A$ \emph{linearly independent} means that $A\mathbf{v} = \mathbf{0}$ implies $\mathbf{v} = \mathbf{0}$.} \\ Matrix $A$ is non-negative definite means $\mathbf{v}^\prime A\mathbf{v} \geq 0$. & ~~~~~ & Matrix $A$ is positive definite means $\mathbf{v}^\prime A\mathbf{v} > 0$ if $\mathbf{v} \neq \mathbf{0}$. \\ $\Sigma = CDC^\prime$ & ~~~~~ & $\Sigma^{-1} = CD^{-1} C^\prime$ \\ $\Sigma^{1/2} = CD^{1/2} \mathbf{C}^\prime$ & ~~~~~ & $\Sigma^{-1/2} = CD^{-1/2} C^\prime$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Random vectors %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% $cov(\mathbf{y}) = E\left\{(\mathbf{y}-\boldsymbol{\mu}_y)(\mathbf{y}-\boldsymbol{\mu}_y)^\prime\right\}$ & ~~~~~ & $cov(\mathbf{y,t}) = E\left\{ (\mathbf{y}-\boldsymbol{\mu}_y) (\mathbf{t}-\boldsymbol{\mu}_t)^\prime\right\}$ \\ $cov(A\mathbf{y}) = A \, cov(\mathbf{y}) A^\prime$ & ~~~~~ & $cov(A\mathbf{y},B\mathbf{y}) = A \, cov(\mathbf{y}) B^\prime$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Multivariate MGF, MVN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% $M_{\mathbf{y}}(\mathbf{t}) = E(e^{\mathbf{t}^\prime\mathbf{y}})$ & ~~~~~ & $M_{A\mathbf{y}}(\mathbf{t}) = M_{\mathbf{y}}(A^\prime\mathbf{t})$ \\ $M_{\mathbf{y}+\mathbf{c}}(\mathbf{t}) = e^{\mathbf{t}^\prime\mathbf{c}} M_{\mathbf{y}}(\mathbf{t})$ & ~~~~~ & $\mathbf{y} \sim N_p(\boldsymbol{\mu}, \Sigma)$ means $M_{\mathbf{y}}(\mathbf{t}) = e^{\mathbf{t}^\prime\boldsymbol{\mu} + \frac{1}{2} \mathbf{t}^\prime \Sigma \mathbf{t}}$ \\ \multicolumn{3}{l}{$\mathbf{y}_1$ and $\mathbf{y}_2$ are independent if and only if $M_{(\mathbf{y}_1,\mathbf{y}_2)}\left(\mathbf{t}_1,\mathbf{t}_2\right) = M_{\mathbf{y}_1}(\mathbf{t}_1) M_{\mathbf{y}_2}(\mathbf{t}_2)$} \\ If $\mathbf{y} \sim N_p(\boldsymbol{\mu}, \Sigma)$, then $A\mathbf{y} + \mathbf{c} \sim N_q(A\boldsymbol{\mu}+\mathbf{c}, A\Sigma A^\prime)$, & ~~~~~ & and $w = (\mathbf{y}-\boldsymbol{\mu})^\prime \Sigma^{-1}(\mathbf{y}-\boldsymbol{\mu}) \sim \chi^2(p)$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Regression (normal next time) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% $y_i = \beta_0 + \beta_1 x_{i1} + \cdots + \beta_k x_{ik} + \epsilon_i$ & ~~~~~ & $\epsilon_1, \ldots, \epsilon_n$ independent $N(0,\sigma^2)$ \\ $\mathbf{y} = X \boldsymbol{\beta} + \boldsymbol{\epsilon}$ with $\boldsymbol{\epsilon} \sim N(\mathbf{0},\sigma^2I_n)$ & ~~~~~ & $\mathbf{b} = (X^\prime X)^{-1} X^\prime \mathbf{y} \sim N_{k+1}\left(\boldsymbol{\beta},\sigma^2(X^\prime X)^{-1}\right)$ \\ $\widehat{\mathbf{y}} = X\mathbf{b} = H\mathbf{y}$, where $H = X(X^\prime X)^{-1} X^\prime $ & ~~~~~ & $\mathbf{e} = \mathbf{y} - \widehat{\mathbf{y}} = (I-H)\mathbf{y}$ \\ $\mathbf{b}$ and $\mathbf{e}$ are independent under normality. & ~~~~~ & $\frac{SSE}{\sigma^2} = \frac{\mathbf{e}^\prime \mathbf{e}}{\sigma^2} \sim \chi^2(n-k-1)$ \\ $\sum_{i=1}^n(y_i-\overline{y})^2 = \sum_{i=1}^n(y_i-\widehat{y}_i)^2 + \sum_{i=1}^n(\widehat{y}_i-\overline{y})^2$ & ~~~~~ & $SST=SSE+SSR$ and $R^2 = \frac{SSR}{SST}$ \\ $t = \frac{Z}{\sqrt{W/\nu}} \sim t(\nu)$ & ~~~~~ & $F = \frac{W_1/\nu_1}{W_2/\nu_2} \sim F(\nu_1,\nu_2)$ \\ $t = \frac{\boldsymbol{\ell}^\prime \mathbf{b}-\boldsymbol{\ell}^\prime \boldsymbol{\beta}} {s \sqrt{ \boldsymbol{\ell}^\prime (X^\prime X)^{-1}\boldsymbol{\ell}}} \sim t(n-k-1)$ & ~~~~~ & $\boldsymbol{\ell}^\prime \mathbf{b} \pm t_{\alpha/2} \, s \sqrt{ \boldsymbol{\ell}^\prime (X^\prime X)^{-1}\boldsymbol{\ell}}$ \\ $F^* = \frac{(\mathbf{C}\mathbf{b}-\boldsymbol{\gamma})^\prime (\mathbf{C}(\mathbf{X}^\prime \mathbf{X})^{-1}\mathbf{C}^\prime)^{-1} (\mathbf{C}\mathbf{b}-\boldsymbol{\gamma})} {m \, s^2} \stackrel{H_0}{\sim} F(m,n-k-1)$ & ~~~~~ & $F^* = \frac{SSR_F-SSR_R}{m \, s^2} = \left( \frac{n-k-1}{m} \right) \left( \frac{a}{1-a} \right)$ \\ $s^2 = \frac{SSE}{n-k-1} = \frac{\mathbf{e}^\prime \mathbf{e}}{n-k-1}$ & ~~~~~ & $a = \frac{R^2_F-R^2_R}{1-R^2_R} = \frac{mF}{n-k-1+mF}$ \\ $t = \frac{y_0 - \mathbf{x}_0^\prime \mathbf{b}} {s \sqrt{1+\mathbf{x}_0^\prime (X^\prime X)^{-1}\mathbf{x}_0}} \sim t(n-k-1)$ & ~~~~~ & $\mathbf{x}_0^\prime \mathbf{b} \pm t_{\alpha/2} \, s \sqrt{1+\mathbf{x}_0^\prime (X^\prime X)^{-1}\mathbf{x}_0}$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \end{tabular} \renewcommand{\arraystretch}{1.0} \begin{center}\begin{tabular}{l} \hspace{6.5in} \\ \hline \end{tabular}\end{center} This formula sheet was prepared by \href{http://www.utstat.toronto.edu/~brunner}{Jerry Brunner}, Department of Statistics, University of Toronto. It is licensed under a \href{http://creativecommons.org/licenses/by-sa/3.0/deed.en_US} {Creative Commons Attribution - ShareAlike 3.0 Unported License}. Use any part of it as you like and share the result freely. The \LaTeX~source code is available from the course website: \begin{center} \href{http://www.utstat.toronto.edu/~brunner/oldclass/302f17} {\texttt{http://www.utstat.toronto.edu/$^\sim$brunner/oldclass/302f17}} \end{center} \end{document} % Next time: Prediction interval $t = \frac{y_0 - \mathbf{x}_0^\prime \mathbf{b}} {s \sqrt{1+\mathbf{x}_0^\prime (X^\prime X)^{-1}\mathbf{x}_0}} \sim t(n-k-1)$ & ~~~~~ & $\mathbf{x}_0^\prime \mathbf{b} \pm t_{\alpha/2} \, s \sqrt{1+\mathbf{x}_0^\prime (X^\prime X)^{-1}\mathbf{x}_0}$ \\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% & ~~~~~ & \\