A major car manufacturer wants to test a new catalytic converter to determine whether it meets new air pollution standards. The mean emission of all converters of this type must be less than 20 parts per million of carbon. Ten (10) converters are manufactured for testing purposes and their emission levels are measured with a mean of 17.17 and a standard deviation of 2.98. Assume measurements are normally distributed.
-The null and alternative hypotheses to support the claim that the mean emission level for all converters of this type is less than 20 ppm is _____.

Question

Quizplus · Accepted Answer

The null hypothesis should always state that there is no significant difference or effect, so the null hypothesis is that the mean emission level is greater than or equal to 20 ppm. The alternative hypothesis should state the opposite, that there is a significant difference or effect, so the alternative hypothesis is that the mean emission level is less than 20 ppm. Therefore, the correct choice is B, which states H₀: μ ≥ 20 vs. H_a: μ < 20. The other choices either have incorrect inequality signs or use a value for the mean that is not mentioned in the problem.

A Major Car Manufacturer Wants to Test a New Catalytic