The EPA has stipulated that the Pollution Standard Index (PSI)for clean air standards is to average no more than 100.A random sample of 9 days for the city of Acorn showed PSI readings of 144,85,90,120,150,105,93,130,and 115.Assume the population of PSI readings is highly nonnormal.Is there significant evidence to conclude that Acorn's air is dirtier than the stipulated clean air standards? Test at α = .05.
A)Reject the null hypothesis.
B)Do not reject the null hypothesis.

Question

Quizplus · Accepted Answer

Since the population is highly nonnormal and the sample size is small (n=9), a non-parametric test like the Wilcoxon signed-rank test should be used. However, if we calculate the sample mean (115.78) and compare it to the stipulated standard (100), the evidence is not strong enough to reject the null hypothesis at α = .05.

The EPA Has Stipulated That the Pollution Standard Index (PSI)for