Exercise 13.4: The correlation time

Consider $L=8$ and $T=3.0$ (high $T$) and $T=2.3$, and $T=1.5$ (low $T$). Estimate the correlation time $\tau$ for the energy and the magnetization fluctuations. Are the values comparable for the two fluctuations? How do your estimates for $\tau$ compare with your estimates for the relaxation time found in the previous problem?