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A recent study reported that for a sample of 50 kitchens with gas cooking appliances monitored...

A recent study 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 726.15, and the sample standard deviation was 133.56.

a) Calculate and interpret 90%, 95% and 99% confidence interval for true average CO2 level in the population of all homes from which the sample was selected.

b) Approximating population standard deviation with sample standard deviation, what sample size would be necessary to obtain an interval width of 55 ppm for a confidence level of 95%?

Math   Statistics-And-Probability   
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