Question

"Call me: A sociologist wants to construct a 95% confidence interval for the proportion of children aged 8–12 living in NewYork who own a cell phone.a. A survey by the National Consumers League estimated the nationwide proportion to be 0.56. Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.02?b. Estimate the sample size needed if no estimate of p is31. Changing jobs: A sociologist sampled 200 people who work available.in computer-related jobs, and found that 42 of them have changed jobs in the past 6 months. A. Construct a 95% confidence interval for the proportion of B. Estimate the sample size needed if no estimate of p is available. C. If the sociologist wanted to estimate the proportion in the entire United States rather than in New York, would the necessary sample size be larger, smaller, or about the same?"

Answer 1

Using Z table, critical value of confidence interval is 1.96