A research article reported that for a sample of 50 kitchens with gas cooking appliances monitored during a one-week period, the sample mean CO2 level (ppm) was 654.16, and the sample standard...

Extracted text: A research article reported that for a sample of 50 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 164.43. (a) Calculate a 95% two-sided confidence interval for true average CO2 level in the population of all homes from which the sample was selected. (Give your answer to 2 decimal places) Answer: ( (b) Suppose the investigators had made a rough guess of 175 for the value of the sample standard deviation s before collecting data. What is the smallest sample size n necessary to obtain an interval width of 50 ppm for a confidence level of 95%? Round your answer up to the nearest whole number. n =