The following table contains a distribution obtained in 320 tosses of 6 coins and the corresponding expected frequencies calculated with the formula for the binomial distribution for $p=0.5$ and $n=6$.

\begin{tabular}{l|rrrrrrr} No. heads & 0 & 1 & 2 & 3 & 4 & 5 & 6 \ \hline Observed frequencies & 3 & 21 & 85 & 110 & 62 & 32 & 7 \ Expected frequencies & 5 & 30 & 75 & 100 & 75 & 30 & 5 \end{tabular}

Conduct a goodness-of-fit test at the $0.05$ level for the null hypothesis that the coins are all fair.

[Hint:

$\left.\begin{array}{lcccc}\text { Distribution } & \chi_{5}^{2} & \chi_{6}^{2} & \chi_{7}^{2} \\ 95 \% \text { percentile } & 11.07 & 12.59 & 14.07 & \end{array}\right]$