products for error:</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>             mb          bh         bl        nh</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> mb 3061.066667    5.333333   11.46667  291.3000</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> bh    5.333333 3405.266667  754.00000  412.5333</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> bl   11.466667  754.000000 3505.96667  164.3333</span>
<span class="r-out co"><span class="r-pr">#&g