In general, the results of Procedure 2 may not have shown clear-cut evidence that the period increases as dramatically with the angle as Eq. (4.1) might suggest. To understand why, write Eq. $(4.1)$ as
$$
T=T_{1}\left(1+\frac{1}{4} \sin ^{2} \frac{\theta}{2}+\frac{9}{64} \sin ^{4} \frac{\theta}{2}\right)
$$
and compute $T$ in terms of $T_{1}\left(\right.$ where $\left.T_{1}=2 \pi \sqrt{\frac{L}{g}}\right)$ for angles of $5^{\circ}, 20^{\circ}$, and $60^{\circ}$.
Comment on the theoretical predictions and experimental accuracy in relation to your results in Data Table $1 .$