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I have an estimated equation with both coefficients and t-statistics. It's a multiline equation and would like to put the t-statistics right below the coefficient estimates Currently my code looks like this:

\begin{equation}\label{eq:test}
\begin{split}
EST =& 4.00 - 7.00BETA - 2.00SMB + 8.00HML + 3.00MOM + 1.00SMBU - \\
  & (8.00)  (-2.20) (-1.60) (9.00) (3.00) (1.00) \\
  & 1.00TERMR - 1.00SMBH +  1.00SMBL +  0.00SMBK -  1.30HMLR.\\
  & (-1.11) (1.53) (6.81) (2.14) (-1.85)
\end{split}
\end{equation}

So the 4.00 in the first line should be right above the (8.00) from the line below. The 7.00 in the first line should be exactly above the (-2.20). The 2.00 in the first line should be right above the (-1.60) and so on for the other coefficient and t-statistics, respectively. It should look like equation (1) from the Fama/French (1993) paper for those of you who are into finance:

enter image description here

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2 Answers 2

up vote 1 down vote accepted

There are many ways to achieve this. Here's one where a [t]op-aligned array is used to place the coefficient and stacked below with the t-statistic. This is all achieved via \coeft{<coef>}{<t-stat>}:

enter image description here

\documentclass{article}
\usepackage{mathtools}% http://ctan.org/pkg/amsmath
\newcommand{\coeft}[2]{
  \begin{array}[t]{@{}c@{}}
    #1\\[\dimexpr-\normalbaselineskip+1em]
    \scriptstyle\mathclap{(#2)}
  \end{array}}
\begin{document}

\begin{equation}\label{eq:test1}
\begin{split}
EST =& 4.00 - 7.00BETA - 2.00SMB + 8.00HML + 3.00MOM + 1.00SMBU - \\
  & (8.00)  (-2.20) (-1.60) (9.00) (3.00) (1.00) \\
  & 1.00TERMR - 1.00SMBH +  1.00SMBL +  0.00SMBK -  1.30HMLR.\\
  & (-1.11) (1.53) (6.81) (2.14) (-1.85)
\end{split}
\end{equation}

\begin{equation}\label{eq:test2}
\begin{split}
  \text{EST} &= \coeft{4.00}{8.00} - \coeft{7.00}{-2.20}\text{BETA} 
    - \coeft{2.00}{-1.60}\text{SMB} + \coeft{8.00}{9.00}\text{HML} 
    + \coeft{3.00}{3.00}\text{MOM} + \coeft{1.00}{1.00}\text{SMBU} \\
  & \phantom{=}{} - \coeft{1.00}{-1.11}\text{TERMR} - \coeft{1.00}{1.53}\text{SMBH} 
    +  \coeft{1.00}{6.81}\text{SMBL} +  \coeft{0.00}{2.14}\text{SMBK} 
    -  \coeft{1.30}{-1.85}\text{HMLR.}
\end{split}
\end{equation}

\end{document}

Some changes to your code include using:

  • \text{<var>} to represent the variable <var>. Otherwise, for say BETA, TeX will consider this as a product between the variables (letters) B, E, T and A;
  • &= rather than =& for the alignment of the equation;
  • spacing techniques such as \phantom{=} to obtain the correct indentation at alignment around =;
  • {} before binary operators that have no counterpart in order to obtain the correct spacing (see the minus sign before 1.00TERMR, which would otherwise have been seen as a unary/negative sign;
  • \scriptstyle to represent the t-statistics, to not emphasize these as being part of the equation.

mathtools provides \mathclap which is a centred overlap in math mode so that any of the t-statistics do not influence the equation spacing.

Of course, you can modify \coeft to your liking. I've included the brackets (), but this can be removed.

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Worked great! Thank you very much! –  ben Apr 25 '13 at 21:03
\begin{equation}\label{eq:test}
\begin{array}{*7{l}}
EST =& 4.00& {}- 7.00BETA& {}- 2.00SMB&{} + 8.00HML& + 3.00MOM& + 1.00SMBU - \\
  & (8.00)&  (-2.20)& (-1.60)& (9.00)& (3.00)& (1.00) \\
  & 1.00TERMR& - 1.00SMBH& +  1.00SMBL &+  0.00SMBK &-  1.30HMLR.&\\
  & (-1.11) &(1.53)& (6.81)& (2.14) &(-1.85)&
\end{array}
\end{equation}

This is a general idea. Some adjustments, especially {} groups (three of them added), are needed.

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