In 2018 , consumer goods giant Procter and Gamble (P\&G) had more than 20 brands with more than $\$ 1$ billion in annual sales $(\mathrm{P} \& \mathrm{G}$ website, https://us.pg.com/). How does a company like $\mathrm{P} \& \mathrm{G}$ create so many successful consumer products? $\mathrm{P} \& \mathrm{G}$ effectively invests in research and development to understand what consumers want. One method used to determine consumer preferences is called conjoint analysis. Conjoint analysis allows a company to ascertain the utility that a respondent in the conjoint study places on a design of a given product. The higher the utility, the more valuable a respondent finds the design. Suppose we have conducted a conjoint study and have the following estimated utilities (higher is preferred) for each of three different designs for a new whitening toothpaste.
$$
\begin{array}{rrrr}
\multicolumn{4}{c} {\text { Utilities }} \\
\text { Respondent } & \text { Design A } & \text { Design B } & \text { Design C } \\
1 & 24.6 & 34.6 & 28.6 \\
2 & 31.4 & 31.6 & 33.7 \\
3 & 31.8 & 20.4 & 27.6 \\
4 & 15.4 & 26.6 & 24.9 \\
5 & 20.7 & 18.5 & 18.0 \\
6 & 41.0 & 34.2 & 44.6 \\
7 & 27.1 & 22.7 & 27.1 \\
8 & 20.2 & 22.0 & 27.7 \\
9 & 31.6 & 29.6 & 31.1 \\
10 & 24.4 & 29.2 & 29.1
\end{array}
$$
At the .05 level of significance, test for any significant differences.