The makers of the MAGNETIZER Engine Energizer System (EES) claim that it improves gas mileage and reduces emissions in automobiles by using magnetic free energy to increase the amount of oxygen in the fuel for greater combustion efficiency. Following are test results, performed under international and U.S. Government agency standards, on a random sample of 14 vehicles. The data give the carbon monoxide (CO) levels, in parts per million, of each vehicle tested, both before installation of EES and after installation.
Suppose that you want to perform a hypothesis test to determine whether, on average, EES reduces CO emissions. Conduct preliminary graphical data analyses to decide whether applying the paired t-test is reasonable. Explain your decision.
Answer to relevant QuestionsIn the article "Improved Outcome for Children With Disseminated Adenoviral Infection Following Allogeneic Stem Cell Transplantation" (British Journal of haematology, Vol. 130, Issue 4, p. 595), B. Kampmann et al. examined ...This exercise shows what can happen when a hypothesis-testing procedure designed for use with independent samples is applied to perform a hypothesis test on a paired sample. The gas mileages, in miles per gallon (mpg), of 10 ...A variable of two populations has a mean of 40 and a standard deviation of 12 for one of the populations and a mean of 40 and a standard deviation of 6 for the other population. Moreover, the variable is normally distributed ...x1 = 10, s1 = 2.1, n1 = 15, x2 = 12, s2 = 2.3, n2 = 15 a. Two-tailed test, α = 0.05 b. 95% confidence interval We have provided summary statistics for independent simple random samples from two populations. In each case, ...V. Tangpricha et al. did a study to determine whether fortifying orange juice with Vitamin D would result in changes in the blood levels of five biochemical variables. One of those variables was the concentration of ...
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