1.Use margin of error, confidence level, and standard deviation to find the minimum sample size required to estimate an unknown population mean.

Margin of error: $124, Confidence level; 99%, σ = $560

2.Find the margin of error for 95% confidence interval used to estimate the population propprtion.

In a clinical test with 2333 subjects, 50% showed improvement from the treament.

Thank, I'm having a hard time figure how to get the answers here.