If the probability distribution is given by,
\[
\begin{array}{|c|c|c|c|c|}
\hline
x & 0 & 1 & 2 & 3 \\
\hline
p(n) & 8a-1 \, /30 & 4a-1 \, /30 & 2a+1 \, /30 & b \\
\hline
\end{array}
\]
If it is given that \( \sigma^2 + \mu^2 = 2 \), where \( \sigma \) is the standard deviation and \( \mu \) is the mean of the distribution, then \( \frac{a}{b} \) is: