A student measures the time period of $100$ oscillations of a simple pendulum four times. The data set is $90\; s, 91\; s, 95\; s\; and\; 92\; s$. If the minimum division in the measuring clock is $1\; s$, then the reported mean time should be :

Question

$\begin{array}{1 1} (1)92 \pm 2\;s \\ (2)92 \pm 5.0\;s \\ (3)92 \pm 1.8\;s \\ (4)92 \pm 3\;s\end{array}$