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In 2017, The Entire Fleet Of Light-duty Vehicles Sold In The United States By Each Manufacturer Must Emit An Average Of No More Than 86 Milligrams Per Mile (mg/mi) Of Nitrogen Oxides (NOX) And Nonmethane Organic Gas (NMOG) Over The Useful Life (150,000 Miles Of Driving) Of The Vehicle. NOX + NMOG Emissions Over The Useful Life For One Car Model Vary Normally With Mean 80 Mg/mi And Standard Deviation 4 Mg/mi. (a) What Is The Probability That A Single Car Of This Model Emits More Than 86 Mg/mi Of NOX + NMOG? (b) A Company Has 25 Cars Of This Model In Its Fleet. What Is The Probability That The Average NOX + NMOG Level X¯ Of These Cars Is Above 86 G/mi? - Math Discussion

In 2017, the entire fleet of light-duty vehicles sold in the United States by each manufacturer must emit an average of no more than 86 milligrams per mile (mg/mi) of nitrogen oxides (NOX) and nonmethane organic gas (NMOG) over the useful life (150,000 miles of driving) of the vehicle. NOX + NMOG emissions over the useful life for one car model vary Normally with mean 80 mg/mi and standard deviation 4 mg/mi. (a) What is the probability that a single car of this model emits more than 86 mg/mi of NOX + NMOG? (b) A company has 25 cars of this model in its fleet. What is the probability that the average NOX + NMOG level x¯ of these cars is above 86 g/mi?