The Occupational Safety and Health Administration (OSHA) hasidentified the gaseous chemical benzene as a possiblecancer-causing substance. A federal regulation requires factoriesto keep the amount of benzene in the air at or below 1 part permillion (ppm). OSHA sends an investigator to inspect the airquality at a certain factory. The factory’s manager insists thattheir air quality is safe. In OSHA’s investigation, they collected20 random air samples from the factory and found a mean benzenecontent of 1.4 ppm with a standard deviation of 1.25 ppm.
At a significance level of 0.01, conduct a hypothesis test forthe claim, “The air in this factory has a mean benzene content thatis less than or equal to 1 ppm.â€
1. Select the pair of hypotheses that are appropriatefor testing this claim.
| | H0: µ > 1 (claim)
H1: µ ≤ 1 |
| | H0: µ ≥ 1
H1: µ < 1 (claim) |
| | H0: µ < 1
H1: µ ≥ 1 (claim) |
| | H0: µ ≤ 1
H1: µ > 1 (claim) |
| | H0: µ ≥ 1 (claim)
H1: µ < 1 |
| | H0: µ ≤ 1 (claim)
H1: µ > 1 |
| | H0: µ < 1 (claim)
H1: µ ≥ 1 |
| | H0: µ > 1
H1: µ ≤ 1 (claim) |
2. Select the choice that best describes the nature anddirection of a hypothesis test for this claim.
| | This is a right-tail t-test for µ. |
| | This is a left-tail t-test for µ. |
| | This is a two-tail z-test for µ. |
| | This is a left-tail z-test for µ. |
| | This is a two-tail t-test for µ. |
| | This is a right-tail z-test for µ. |
3. Find the standardized test statistic for thishypothesis test. Round your answer to 2 decimalplaces.
4. Find the P-value for this hypothesis test. Round youranswer to 4 decimal places.
5. Using your previous calculations, select the correctdecision for this hypothesis test.
6. Consider the following statements related to theclaim. Based on the results of your hypothesis test, which of thesestatements is true? Select the best choice.
