A political candidate has asked you to conduct a poll to determine what percentage of people support her. If the candidate only wants a 2% margin of error at a 99% confidence level, what size of sample is needed? Do not round between steps. Use technology to find z-score. Give your answer in whole people. Make sure you use the correct rounding rule for sample size.
Out of 400 people sampled, 280 preferred Candidate A. Based on this, estimate what proportion of the voting population (p) prefers Candidate A. Use a 99% confidence level, and give your answers as decimals, to three places.
You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately σ = 37.4. You would like to be 98% confident that your estimate is within 4 of the true population mean. How large of a sample size is required? n =
A random sample of 40 people who owned their own business reported a yearly mean profit of $12,190 with a standard deviation of $1,700. Find the 92% confidence interval for the population mean. (Round your answers to the nearest dollar)