# Latex Table giving me an error

\begin{table}
\begin{tabular}{|c|c|c|c|c|}
\hline
\multicolumn{5}{|c|}{\textbf{Table 1:}Unfiltered Water}\\
Concentration of analyte in sample   & Avg & Std Dev &  RSD & 90\% CI \\
\hline
Total hardness (ppm $CaCo_3$ equiv)  & 97  &    2   &  2\%  & \pm 5   \\
Calcium hardness (ppm $Ca^{2+}$)     & 57  &    3   &  5\%  &  \pm 5   \\
Magnesium hardness( ppm $Mg^{2+}$)   & 40  &    3   & 7.5\% &  \pm 5 \\
\hline
\end{tabular}


This table is giving me an error. That says

! Missing $inserted. <inserted text>$
l.41 ...Co_3 equiv\) & 97 & 2 & 2\% & \pm
5 \\


I've inserted a begin-math/end-math symbol since I think you left one out. Proceed, with fingers crossed.

What is the cause of this error? I can't seem to find any thing that is mismatched.

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\pm requires math mode, that's all. Since tabular sets its contents in text mode, it causes an error, and you have to switch manually using $\pm$. It's better to use \pm 5 though. –  Werner Oct 6 '13 at 23:21
You also should say CaCO$_3$ or use a specialized package for inputting chemical formulas such as mhchem or bpchem. –  egreg Oct 6 '13 at 23:26
I have tried to use mhchem in Texmaker, but the package is not there. Is there an easy way to install packages? Is there a package manager for Texmaker? –  olliepower Oct 6 '13 at 23:41
@Werner I agree \pm 5 is better. But is there a way to input it, with out generating an error? –  olliepower Oct 6 '13 at 23:43
Why do you write "Table 1" in the table? You can use the \caption{} command for automatic numbering! Details for this can be found in every basic latex tutorial dealing with floating environments such as figure or table –  Martin H Oct 6 '13 at 23:46

The use of \pm requires math-mode, so you should use $\pm 5$.

Here is a full alternative view on your table using booktabs (for pizzaz...), caption (for caption formatting) and mhchem (for Chemistry formula setting):

\documentclass{article}
\usepackage{booktabs,caption,mhchem}
\captionsetup{labelfont=bf, textfont=normalfont}
\begin{document}
\begin{table}
\caption{Unfiltered water}
\begin{tabular}{*{5}{c}}
\toprule
Concentration of analyte in sample   & Avg & Std Dev &  RSD             &  90\% CI \\
\midrule
Total hardness (ppm \ce{CaCo_3} equiv)  & 97  &    2    &  \phantom{0.}2\% & $\pm 5$  \\
Calcium hardness (ppm \ce{Ca^{2+}})     & 57  &    3    &  \phantom{0.}5\% & $\pm 5$  \\
Magnesium hardness (ppm \ce{Mg^{2+}})   & 40  &    3    &            7.5\% & $\pm 5$  \\
\bottomrule
\end{tabular}
\end{table}

\end{document}


Original:

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