\begin{table}%T2
%\centering
\par
\caption{Linear regression analysis of sample data ($B$ is expressed in G,
$1 \sigma$ errors of $a$ and $b$ are shown in brackets).}\label{tab2}
\par
\begin{tabular}{llrcc}
\hline\hline
Observatories&Year&$m$&Equation&$r$\\
($x$--$y$)&&&$(y = a + b \times x)$&\\
\hline
MWO--WSO&1979&191&$y = + 0.09 ~(0.03) + 0.28 ~(0.03) \times x$&0.67\\
-- " -- &1981&179&$y = + 0.06 ~(0.04) + 0.54 ~(0.04) \times x$&0.77\\
-- " -- &1982&175&$y = + 0.03 ~(0.04) + 1.20 ~(0.07) \times x$&0.80\\
\hline
-- " -- &1975--1982&1442&$y = + 0.02 ~(0.01) + 0.35 ~(0.02) \times x$&0.58\\
\hline
CrAO--MWO&1970--1976&665&$y = + 0.03 ~(0.03) + 0.27 ~(0.04) \times x$&0.26\\
\hline
CrAO--WSO&1991&25&$y = + 0.30 ~(0.07) + 0.70 ~(0.06) \times x$&0.94\\
-- " -- &1999&103&$y = + 0.02 ~(0.03) + 0.36 ~(0.04) \times x$&0.70\\
-- " --  &2001&57&$y = + 0.05 ~(0.03) + 0.25 ~(0.06) \times x$&0.52\\
\hline
-- " --&1975--2001&712&$y = + 0.08 ~(0.01) + 0.33 ~(0.02) \times x$&0.65\\
\hline
SSO--MWO&1982&32&$y = - 0.03 ~(0.05) + 0.47 ~(0.04) \times x$&0.81\\
\hline
SSO--WSO&1983&84&$y = - 0.06 ~(0.04) + 0.46 ~(0.05) \times x$&0.81\\
-- " -- &1993&28&$y = - 0.10 ~(0.04) + 0.72 ~(0.15) \times x$&0.75\\
\hline
-- " -- &1982--1993&256&$y = - 0.05 ~(0.02) + 0.51 ~(0.03) \times x$&0.77\\
\hline
\end{tabular}
\end{table}