Ten Different Families Are Tested for the Number of Litres

Essay

Ten different families are tested for the number of litres of water a week they use before and after viewing a conservation video.Do the data suggest that the amount after the viewing differs from the amount before the viewing? Perform a Wilcoxon signed rank test at the 5% significance level. $$\begin{array} { c | c c c c c c c c c c } \hline \text { Before } & 33 & 33 & 38 & 33 & 35 & 35 & 40 & 40 & 40 & 31 \\\hline \text { After } & 34 & 28 & 25 & 28 & 35 & 33 & 31 & 28 & 35 & 33 \\\hline \mathbf { B } - \mathbf { A } & - 1 & 5 & 13 & 5 & 0 & 2 & 9 & 12 & 5 & - 2 \\\hline\end{array}$$