1.) Suppose that you want to estimate the average IQ in a community. You have randomly selected 200 residents, and find that they have a mean IQ of 103. Having done some research, you are willing to accept the estimate of approximately 15 as the population standard deviation for IQ scores, so you set σ at 15. You set alpha at .05. What is your estimate?

This one I have no idea where to even start. I'm very confused.

2.)A national polling organization wants to be able to predict the outcome of presidential races to within � 2%. If they set alpha at .05, how large of a sample will be needed to ensure this level of precision?

I think the sample size needs to be 1,000 people. Not sure if this is correct.

3.)You are asked to estimate the mean income of a community, based on information obtained from a random sample of 70 community members. You find that your sample has a mean income of $82,396, with a standard deviation of $4765. You are to use an alpha of .05. What formula would you use to calculate the confidence interval that they are asking for? Why would you use that formula? Make the calculations using the formula you selected, and report the results.

This one I have no idea what this is even asking.

4.)In a study of 400 students at a state university, researchers found that students studied for an average of 18 hours per week, with a standard deviation of 5. What would the point estimate of the average study time for all students at that university be?

I got 20.2 hours but I think it's wrong.