The Level of Nitrogen Oxides (NO_x) in the Exhaust of Cars

Multiple Choice

The level of nitrogen oxides (NO_x) in the exhaust of cars of a particular model varies Normally, with standard deviation σ= 0.05 gram per mile (g/mi) . A random sample of 12 cars of this particular model is taken and is found to have a mean NO_x emission of x̄= 0.298 g/mi. Government regulations call for NO_x emissions no higher than 0.3 g/mi. Do the data provide evidence that this particular model meets the government regulation? What should you conclude from these data?

A) The null hypothesis is proved at significance level 5%.
B) The alternative hypothesis is proved at significance level 5%.
C) There is evidence supporting the alternative hypothesis at significance level 5%.
D) There is not enough evidence to reject the null hypothesis at significance level 5%.