1. Calculate the margin of error if the necessary requirements are satisfied. Please assume the original population is normally distributed: a. Confidence Level = 95%, n = 78, σ = 6; E = ?
2. A concert promoter wants to estimate the mean age of concertgoers who live in the Chicago area. In a random sample of 70 concertgoers, the mean age is found to be 27.8 years. From past studies, the standard deviation is known to be 1.6 years. Construct a 99% interval for the population
3. You want to conduct a study to determine if people would like to purchase dinner vouchers with their tickets to a particular sporting event. You decide to use a survey. How many people should you ask to complete the survey if you want to be 90% confident that the sample mean is within 3 points from the population mean? From previous studies, the standard deviation is 95.
4. Construct the indicated confidence interval for the population mean μ using a t-distribution: C = 99%, m = 46.9, s = 7, n =9
5. A survey of 1500 adults found that 445 of them own a pet cat. Construct a 95% confidence interval of the true proportion of adults who own a cat.
6. A researcher wants to estimate, with a 95% confidence level the proportion of people who own 3 or more cars. A previous study showed that 23% of people asked owned 3 or more cars. The researcher wants to be accurate within 4%. Find the number of people he needs to ask to meet these criteria.