%%% natural_language.tex	Created      : Wed May 22 18:02:55 2002
%%%			Last modified: Wed May 22 20:32:02 2002
%%% Compile: jlatex natural_language.tex #
\documentclass{jreport}
\begin{document}
�����5.2
\begin{eqnarray}
mean:\ \bar d &=& \frac{1}{n}\sum_{i=1}^{n}d_i \\
variance:\ s^2 &=& \frac{1}{n-1}\sum_{i=1}^{n}(d_i-\bar d)^2
\end{eqnarray}
�����5.3.1
t������(t statistic)
\begin{eqnarray}
t\ statistics:\ t &=& \frac{\bar x - \mu}{\sqrt{\frac{s^2}{N}}} \\
t\ score:\ t &=& \frac{\bar x_1 - \bar x_2}{\sqrt{\frac{s_1^2}{n_1}+\frac{s_2^2}{n_2}}}
\end{eqnarray}
�����5.3.3 $\chi^2$����
\begin{eqnarray}
 \chi^2 = \sum_{i,j}\frac{(O_{ij}-E_{ij})^2}{E_{ij}}
\end{eqnarray}

\end{document}