Error bars not displaying

Microsoft Excel 2002 SP3.
I have data that looks like this:
Median Min Max
Na 0.032617 0.000106 0.387142
Cl 0.0265 0.000017 0.282087
Ca 0.000524 0.0000047 0.0059883
K 0.005523 0.000007 0.038365
Mg 0.0000823 0.0000001 0.0018515
PO4 0.00031 0.00002 0.00105
HCO3 0.001655 0.000262 0.003048
I'm doing a line plot with the first column as the categorical x axis,
and the second column, median, on the y-axis, which is logarithmic. I
then set up error bars using the values in the min and max column
(columns 3 and 4 above) as custom values in the "error amount" part of
the format data series dialog. The max values would be for the plus
side of the error bar, and the min values are for the minus side.

I thought this would work perfectly, however, only the plus side of the
error bar is showing up, not the minus side. And in the format data
series dialog I DO have it set to show both.

So, I was wondering if anyone had run into this before, and if there is
a reason and a solution. I want the minus part of the error bars to
show.

Thank you,
Nicole

Create two new columns for the positive and negative error amount
=Max-Median
=Median-Min