An article reported that for a sample of 58 kitchens with gas cooking appliances monitored during a one-week period, the sample
mean CO2 level (ppm) was 654.16, and the sample standard deviation was 165.4. (a) Calculate and interpret a 95% (two-sided) confidence interval for true average CO2 level in the population of all homes from which the sample was selected. (Round your answers to two decimal places.) , ppm Interpret the resulting interval. We are 95% confident that the true population mean lies below this interval. We are 95% confident that this interval does not contain the true population mean. We are 95% confident that this interval contains the true population mean. We are 95% confident that the true population mean lies above this interval.
(b) Suppose the investigators had made a rough guess of 184 for the value of s before collecting data. What sample size would be necessary to obtain an interval width of 47 ppm for a confidence level of 95%?
