An Appliance Manufacturer Is Interested in Determining Whether the Brand

Multiple Choice

An appliance manufacturer is interested in determining whether the brand of laundry detergent used affects the average amount of dirt removed from standard household laundry loads. An experiment is set up in which 10 laundry loads are randomly assigned to each of four laundry detergents-Brands A, B, C, and D (a total of 40 loads in the experiment) . The amount of dirt removed, y, (measured in milligrams) for each load is recorded and subjected to an ANOVA analysis, including a follow-up Tukey analysis. Which of the following inferences concerning the Tukey results below is incorrect? $\begin{array}{cc}\text { Brands } & \text { Sample Means } \\\hline \mathrm{D} & 186 \\\mathrm{C} & 177 \\\mathrm{~B} & 142 \\\mathrm{~A} & 131\end{array}$

A) $\mu _ { \mathrm { C } } < \mu _ { \mathrm { D } }$
B) $\mu _ { \mathrm { B } } < \mu _ { \mathrm { D } }$
C) $\mu _ { \mathrm { A } } < \mu _ { \mathrm { C } }$
D) $\mu _ { \mathrm { D } } > \mu _ { \mathrm { A } }$