Ammonia in car exhaust. Three-way catalytic converters have been installed in new vehicles in order to reduce pollutants from motor vehicle exhaust emissions.

However, these converters unintentionally increase the level of ammonia in the air. Environmental Science

& Technology (Sept. 1, 2000) published a study on the ammonia levels near the exit ramp of a San Francisco highway tunnel. The data in the table represent daily ammonia concentrations (parts per million) on eight randomly selected days during the afternoon drive time in the summer of a recent year. Find an interval that is likely to contain the ammonia level for a randamly selected day during afternoon drive time.

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1.53 1.50 1.37 1.51 1.55 1.42 1.41 1.48