Fading of Wood Is a Problem with Wooden Decks on Boats

Essay

Fading of wood is a problem with wooden decks on boats. Three varnishes used to retard this aging process were tested to see whether there were any differences among them.
Samples of 10 different types of wood were treated with each of the three varnishes and the amount of fading was measured after three months of exposure to the sun. The data are listed below. Is there evidence of a difference in the probability distributions of the amounts of fading for the three different types of varnish? Apply the Friedman Fr-test to the data. Be sure to specify the null and alternative hypotheses. $\text { Use } \alpha = 0.05$$$\begin{array} { c c c l } & { \text { Varnish } } \\\hline \text { Sample } & 1 & 2 & 3 \\\hline 1 & 5.2 & 4.8 & 5.5 \\2 & 7.8 & 7.0 & 7.6 \\3 & 4.0 & 4.1 & 4.0 \\4 & 6.8 & 5.9 & 6.5 \\5 & 9.0 & 7.4 & 8.4 \\6 & 6.2 & 5.4 & 6.3 \\7 & 4.3 & 4.3 & 4.7 \\8 & 6.7 & 6.8 & 7.0 \\9 & 5.5 & 4.7 & 4.8 \\10 & 5.8 & 5.6 & 5.7 \\\hline\end{array}$$