2. A scientist estimates that the mean nitrogen dioxide level in Calgary is greater than 32 parts per billion. You want to test this estimate. To do so, you determine the nitrogen dioxide levels for 34 randomly selected days. The results (in parts per billion) are listed. At a = 0.06, can you support the scientist's estimate? 24 36 44 35 44 34 29 40 39 41 32 13 33 29 29 43 25 39 25 42 29 22 22 25 14 15 14 29 25 27 22 24 18 17 3. A county is considering raising the speed limit on a road because they claim that the mean speed of vehicles is greater than 45 miles per hour. A random sample of 15 vehicles has a mean speed of 48 miles per hour and a standard deviation of 5.4 miles per hour. At a = 0.10, do you have enough evidence to support the county's claim? You receive a brochure from a large university. The brochure indicates that the mean class size for full-time 4. faculty is fewer than 32 students. You want to test this claim. You randomly select 18 classes and determine the class size of each. The results are listed below. At a = 0.05, can you support the university's claim? 25 29 29 33 32 40 26 28 30 28 25 35 28 36 29 27 30 33 5. A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 750 hours. A random sample of 36 light bulbs has a mean life of 745 hours with a standard deviation of 60 hours. At a = 0.02, do you have enough evidence to reject the manufacturer's claim