The answers to the sub-questions are:
- Critical value \( t_{\alpha/2} = 2.03 \)
- Margin of error \( E = 224.2 \, \text{g} \)
- Confidence interval \( 3003.6 \, \text{g} < \mu < 3452.0 \, \text{g} \)
\[
\boxed{t_{\alpha/2} = 2.03, \, E = 224.2 \, \text{g}, \, 3003.6 \, \text{g} < \mu < 3452.0 \, \text{g}}
\]