Question

One hour carbon monoxide concentrations in the air samples from a large city average 13 ppm with a standard deviation of 9 ppm. Assume that the carbon monoxide concentrations are normally distributed.

Seattle Washington wants to improve the city's carbon footprint by the year 2020. Based off the national results, what does Seattle's carbon monoxide concentration need to be if they want to be in the bottom 10%?

Answer 1