Assignment Exploration of z-scores, CLT, and Confidence Intervals

These are the questions I can't seem to figure out, I've tried everything to finish them.

Question 1.

Find a 95% confidence interval estimate of the mean weight of all women based on a sample of 60 women with a mean sample weight of 150.27. From past studies, the standard deviation is known to be 30.87. Write your answer EXACTLY as is given by Excel. Do not round.

The lower limit is

The upper limit is

Question 2.

In a Gallup poll of 2870 randomly selected adults, 64% said that they played video games at least twice a week. Construct a 95% confidence interval estimate for the proportion of adults who play video games twice a week. Write your answer EXACTLY as is given by Excel. Do not round.

The lower limit is

The upper limit is

Question 3.

An advertising company wants to investigate the mean number of hours spent by an adult (40 and older) using Facebook. How many adults 40 and older need to be surveyed by this company? From past studies, we know that the standard deviation is 4.2 hours. We want to be accurate within 1 hour. Use a confidence level of 90%. Write your answer EXACTLY as is given by Excel. Do not round.

The company needs to survey a minimum of________ adults (40 and older).

Question 4. Find the sample size needed to estimate the percentage of people who have at least one pet at home. Use a 2.3% margin of error; use a confidence level of 95%. Write your answer EXACTLY as is given by Excel. Do not round.

The minimum sample size needed is