Hi! I have two statistics questions that I can't quite figure out. Can someone explain these to me?

Question 1:

In a study of cell phone use and brain hemispheric dominance, an Internet survey was e-mailed to 2486 subjects randomly selected from an online group involved with ears. 1022 surveys were returned. Construct a 90% confidence interval for the proportion of returned surveys.

a) Find the best point estimate of the population proportion p.

b) Identify the value of the margin of error E.

c) Construct the confidence interval.

d) Statement that correctly interprets the confidence interval. Choose:

A. There is a 90% chance that the true value of the population proportion will fall between the lower bound and the upper bound.

B. 90% of sample proportions will fall between the lower bound and the upper bound.

C. One has 90% confidence that the sample proportion is equal to the population proportion.

D. One has 90% confidence that the interval from the lower bound to the upper bound actually does contain the true value of the population proportion.

Question 2:

Part 1:

A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 360 babies were born, and 306 of them were girls. Use the sample data to construct a 99% confidence interval estimate of the percentage of girls born.

Part 2:

Does the method appear to be effective?

a) No , the proportion of girls is not significantly different from 0.5.

b) Yes , the proportion of girls is significantly different from 0.5.